Transcript Connection-oriented internetworking

CO internetworking
(intra-domain + inter-layer)
work in progress
Malathi Veeraraghavan, Xuan Zheng, Zhanxiang Huang
{mv5g, xuan, zh4c}@virginia.edu
Jan. 25, 2005
1/25/2005
1
CO internetworking
(intra-domain + inter-layer)

•
•
•
Terminology, questions
Problem description
Take a cue from CL internetworking
CO internetworking CHEETAH scenario (simple)
– Network-by-network setup
– Continued setup
• CO internetworking: complex scenarios with MPLS,
VLANs, SONET, WDM
• Partial CO segments intermixed with CL segments
• Research problems, key ideas, conclusions
1/25/2005
Malathi Veeraraghavan, Zhanxiang Huang, Xuan Zheng
{mv5g, zh4c, xuan}@virginia.edu
2
Nov. 25, 2004
Terminology
•
•
A switch is a node in which
all interfaces use the same
type of multiplexing
A gateway has interfaces
that use different types of
multiplexing
Circuit based
(position-based)
SDM
TDM
WDM
(space) (time) (freq.)
(FSC)
(TDM) (LSC)
1/25/2005
Network
Internetwork
Types of multiplexing
Packet based (CO)
• Different types of packets
 Connection-oriented IP (2205)
 VLAN (L2SC)
 MPLS (PSC-1)
Note: there is no “CO Ethernet” multiplexing/switching
3
Legend
H
Host
G
Gateway (any type)
IP
IP switch: CL and CO
S
SONET switch
1/25/2005
V
VLAN switch
M
MPLS switch
E Ethernet switch
(by default: CL)
4
Questions
•
Difference between LSP encoding type, switching type and GPID
– Switching type: type of multiplexing used on the links of an end-to-end LSP. 3471
states “This field normally is consistent across all links of an LSP.”
• e.g., TDM, PSC-1
– LSP encoding type: type of data carried on each link of the LSP 3471 says “A link
may support a set of encoding formats, where support means that a link is able to
carry and switch a signal of one or more of these encoding formats depending on
the resource availability and capacity of the link.” 3471: “The LSP Encoding Type
represents the nature of the LSP, and not the nature of the links that the LSP
traverses.” MRN document says “LSP Encoding Type (representing the nature of
the link that the LSP traverses)” and says on a link terminating at a gateway that
can perform PSC, TDM and WDM switching, the LSP encoding is lambda.
• Vijay confirmed my (and MRN) understanding that LSP encoding is below
the switching level (actually all the way below) and GPID is above LSP
• Examples: MPLS switch with PoS link and GbE link. For the PoS link, LSP
encoding should be SONET while switching type: PSC-1 and for the GbE link,
LSP encoding should be Ethernet and switching type: PSC-1. Vijay says that
MPLS specs don’t allow this sort of LSP to be set up. Both switching and LSP
encoding type need to be the same across a “switch” for LSP setup!
– GPID: what’s carried on the LSP end-to-end
1/25/2005
5
Questions
• Nested vs. contiguous vs. stitched LSPs
– Tom: if you don’t treat an LSP as an FA LSP and send it
out in IGP, then it may be regarded as a contiguous LSP.
If there is label stacking, then it is a nested LSP.
Unclear.
• Plain and hybrid nodes: switch and gateway
– Chris: Plain node vs. hybrid node – from mrn document
– how does it relate to my “switch” and “gateway?”
Plain node can also have multiple interface types (from
a mux point of view) but only one mux type is enabled
in a plain node at a time unlike in a hybrid node.
1/25/2005
6
CO internetworking
(intra-domain + inter-layer)
•

•
•
Terminology, questions
Problem description
Take a cue from CL internetworking
CO internetworking CHEETAH scenario (simple)
– Network-by-network setup
– Continued setup
• CO internetworking: complex scenarios with MPLS,
VLANs, SONET, WDM
• Partial CO segments intermixed with CL segments
• Research problems, key ideas, conclusions
1/25/2005
Malathi Veeraraghavan, Zhanxiang Huang, Xuan Zheng
{mv5g, zh4c, xuan}@virginia.edu
7
Nov. 25, 2004
Initial problem
• Simplistic starting point in CHEETAH
– “Optical Connectivity Service” – check to see if far end
has access to CHEETAH service
– Added need to find MAC address of far-end host
• Simplistic answer: Add “OCS available” TXT
resource record to domain name in DNS server.
Add MAC address associated with domain name
again using TXT resource record
• See example in following two slides
1/25/2005
8
A simple scenario:
Ethernet-SONET-Ethernet
End host 1
End host 2
SONET
cloud
Ethernet
SONET
SONET
Ethernet
End host 1 needs to know:
• IP address of End host 2 to set up Ethernet-over-SONET circuit
• MAC address of End host 2 to encapsulate Ethernet frames
1/25/2005
9
DNS based solution for determining availability
of optical connectivity and MAC address
If local DNS does not have the record
End
host 2 registers itself in local
End host 1 finds End for
hostend
2’shost
IP address
2, it will obtain
it through
DNS server with “OCS available”
(using query type A) and
the DNS hierarchy
• availability
Use DNS
to obtain MAC
along
and its address
MAC address
in TXT type
OCS
andserver
MAC address
High-level
Resource Record (RR)
with query
IP address
end host.
(using
type TXT)of far-side
DNS server
Local DNS
server
DNS hierarchy architecture
End host 1
Local DNS
server
End host 2
SONET
cloud
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Ethernet
SONET
SONET
Ethernet
10
Why this approach to obtain MAC address?
•
•
Avoid ARP broadcast going long-distance!
ARP is a fine address resolution scheme if kept local
–
–
•
•
For performance reasons, let’s not add another “50ms” prop. delay just for ARP
Probably more important: avoid broadcast storms at Ethernet switches in both LANs
DNS: natural solution for this mapping; it is already an “address resolution” server
translating domain names to IP addresses. Using the DNS infrastructure to obtain MAC
addresses (wide area) seems a natural extension.
Implementation:
–
–
–
–
1/25/2005
RSVP-TE client at end host 1 writes an entry in the IP routing table (route add) at end host 1
showing that to reach end host 2’s second NIC IP address, next hop is the same IP address. This
removes need to place remote end hosts in same subnet
RSVP-TE client at end host 1 writes an entry in the ARP table mapping end host 2’s second
NIC IP address to obtained MAC address
Comparable to switch fabric configuration actions at a switch
When an IP datagram is handed to the IP module of end host 1, it sees the destination-specific
routing entry in its table and checks ARP table. It finds the MAC address and can encapsulate
the IP frame with Ethernet frame and send out without requiring an ARP.
11
Initial problem description
• Three problems with above simplistic solution:
– Can have CHEETAH-style network islands that are not
interconnected. Even if DNS query confirms “OCS
available” for an end host it may not be on the same
CHEETAH network as the querying host
– Internetwork scenarios: the MAC address to be returned
could be that of a gateway, not the far-end host
– Partial CO internetworking impacts both “OCS
available” and MAC issue.
1/25/2005
12
A more complex scenario:
heterogeneous internetworking
End host 1
End host 2
Ethernet
Switch
VLAN 1
Ethernet
Switch
Ethernet
Switch
MPLS router 1
MPLS router 2
Ethernet
VLAN 2
Switch
Ethernet
2
L3 MPLS
tunnel
In this case, End host 1 needs to know:
• MAC address of the Ethernet interface 1 on router 1
13 1
• 1/25/2005
This should be the destination MAC address in the frames sent by End host
Ethernet
1
More complete problem
(in context; rather than deconstructed)
• Answer four phases for operation of
heterogeneous CO networks
– how should topology/reachability/loading
conditions be advertised through routing
protocols?
– how should paths be pre-computed?
– what signaling parameters and values should be
used in call setup (Path and Resv messages)
– what are the user-plane packet formats?
1/25/2005
14
CO internetworking
• Terminology, questions
• Problem description
 Take a cue from CL internetworking
• CO internetworking CHEETAH scenario (simple)
– Network-by-network setup
– Continued setup
• CO internetworking: complex scenarios with
MPLS, VLANs, SONET, WDM
• Partial CO segments intermixed with CL segments
• Research problems, key ideas, conclusions
1/25/2005
15
Connectionless
Ethernet-IP-Ethernet Scenario
ARP
ARP
MAC
MAC
Network 1
Host A
H
E
I.1
E
Switch 1
(Ethernet)
Switch 2
(Ethernet)
I.2 3.1
G
Gateway I
IP address of
gateway I.1
interface
End-host A’s IP routing table
Internet address
B
II.2
IP
Switch 3
(IP)
Switch 3.1
interface
Router A’s routing table
G
Gateway II
B
H
II.3
E
Switch 4
(Ethernet)
Host B
E
Switch 5
(Ethernet)
Ethernet packet-based
multiplexing on all links
Directly connected
Router B’s routing table
Network 1 address
I.1 interface IP addr. I.1 interface MAC addr.
1/25/2005
3.2
IP multiplexing on all
links
(e.g. all PPP links)
Ethernet packet-based
multiplexing on all links
B
Network 3
Network 2
End-host A’s Internet to network address
mapping table (ARP table)
READ NOTES
16
CO internetworking
• Terminology, questions
• Problem description
• Take a cue from CL internetworking
 CO internetworking CHEETAH scenario
– Network-by-network setup
– Continued setup
• CO internetworking: scenarios with MPLS,
VLANs, SONET, WDM
• Partial CO segments intermixed with CL segments
• Research problems, key ideas, conclusions
1/25/2005
17
Cheetah Scenario:
Dedicated Ethernet-SONET-Dedicated Ethernet
(actually SDM-TDM-SDM)
Routing info distribution phases
Network 1
H
H1
VLSR
GW2 is
a
gateway
VLSR
I.2 3.1
I.1
G
3.2
II.2
G
S
GW1
II.3
GW1 is
a
gateway
H
H2
GW2
SW1
(SONET)
TDM muxing
Internetwork: SDM muxing based network
GW1’s
GW1’s link
link state
state database
database
LSA originated by SW1
Sw. Cap.
Link
Type
Sw. Cap.
GW2
GW2 SW1:3.2-II.2
SW1:3.2-II.2
TDM
GW:I.2-3.1
2
TDM
GW2
GW2
II.3
II.3
FSC
3.2-GW2:II.2
2
TDM
GW1-GW2
FSC/TDM
Router
Router
GW2
Link
Link
1/25/2005
LSA
LSAoriginated
originated by
by GW2
GW2
Link
Link
GW1-GW2
II.3
SW1:3.2-II.2
Type
Type
Sw.
Sw.Cap.
Cap.
Pretend
3
FSC/TDM
FSC
2
18
TDM
Cheetah Scenario:
Dedicated Ethernet-SONET-Dedicated Ethernet
(actually SDM-TDM-SDM)
Path-computation phases
Network 1
VLSR
H
H1
VLSR
I.2 3.1
I.1
G
GW1
3.2
S
SW1
II.2
H
II.3
G
H2
GW2
(SONET)
TDM muxing
Internetwork: SDM muxing based network Outer routing table
GW1’s Link State Database
Dest
Next hop
CO type
H2
GW2
SDM
Router
Link
Sw. Cap.
GW2
GW1-GW2
FSC/TDM
GW2
II.3
FSC
Dest
Next hop
CO type
…
GW2
SW1
TDM
1/25/2005
…
…
CSPF
Inner routing table
19
Cheetah Scenario:
Dedicated Ethernet-SONET-Dedicated Ethernet
(actually SDM-TDM-SDM)
Signaling phase (network-by-network setup: nested LSPs)
Network 1
PATH
VLSR
VLSR
RESV
H1
H
I.2 3.1
I.1
3.2
II.2
H
II.3
G
S
G
GW1
SW1
GW2
H2
(SONET)
H2
GW1
TDM muxing
Internetwork: SDM muxing based network
READ NOTES
End-host A’s CO IP
routing table
(consulted by RSVPTE client)
Path
ResvDest
H2-GW2-GW1-H1
H1-GW1-GW2-H2
H2
1/25/2005
GW1-SW1-GW2GW1-SW1-GW2
GW2
BW
Stack
of labelsLSP enc.
Sw. cap.
H2
MAC Tspec
(know to generate
because
of GPID)
Intserv
FSC this
Fiber
or Ethernet?
SONET Tspec
GW2
TDMMAC SONET/SDH
GPID
Ethertype
20
SONET/SDH
Cheetah Scenario:
Dedicated Ethernet-SONET-Dedicated Ethernet
(actually SDM-TDM-SDM)
User-plane: Data-flow phase
Network 1
H2 H2
Data
MAC IP
H1
H
VLSR
VLSR
SONET H2 H2
Data
frameI.1MAC IPI.2 3.1
G
GW1
3.2
H2 H2
Data
II.2 IP
II.3
MAC
S
SW1
G
H
H2
GW2
(SONET)
TDM muxing
Internetwork: SDM muxing based network
H2
GW1
End-host A’s CO IP
routing table
1/25/2005
(consulted
by RSVPTE client)
21
Cheetah Scenario:
Dedicated Ethernet-SONET-Dedicated Ethernet
(actually SDM-TDM-SDM)
(continued setup: also a nested LSP!)
Network 1
PATH
VLSR
VLSR
RESV
H1
H
I.2 3.1
I.1
G
GW1
3.2
S
SW1
II.2
II.3
G
H
H2
GW2
(SONET)
Internetwork: SDM muxing based network
H2
GW1
End-host A’s CO IP
routing table
(consulted
by RSVP1/25/2005
TE client)
Doesn’t seem to be a good solution; mismatches
in crossconnect rates (e.g., lambda);
gets complex if VCAT necessitates multiple LSPs
READ NOTES
22
CO internetworking
•
•
•
•
Terminology, questions
Problem description
Take a cue from CL internetworking
CO internetworking CHEETAH scenario (simple)
– Network-by-network setup
– Continued setup
 CO internetworking: complex scenarios with
MPLS, VLANs, SONET, WDM
• Partial CO segments intermixed with CL segments
• Research problems, key ideas, conclusions
1/25/2005
23
Before we start with the scenarios
• Learn what current gateway implementations
actually do
• Some background on OSPF, OSPF-TE and
GMPLS extensions
• Key idea: Pretend links; allows for homogeneous
LSPs to be setup in nested mode
• Outermost network: SDM, VLAN, IP
– Two points
1/25/2005
24
User-plane capabilities
(to support CO internetworking)
• Three types of gateways:
– Summit Extreme
• SDM ↔ VLAN (untagged ports to tagged VLANs)
– Cisco GSRs
• IP ↔ MPLS
• VLAN ↔ MPLS
• SDM ↔ VLAN (port mapped Ethernet over MPLS)
– Cisco 15454/Movaz
•
•
•
•
1/25/2005
SDM ↔ SONET
SDM ↔ WDM
VLAN ↔ SONET? (Ethernet cards in 454)?
IP ↔ SONET? (ML series cards in 454)?
25
User-plane capabilities
(to support CO internetworking)
• Summit Extreme
– Can crossconnect SDM to VLAN
– Meaning place an untagged port (port mapped) to a
VLAN along with a tagged port (with a VLAN ID)
– Switch is capable of popping on label (VLAN ID) and
popping it off if outgoing port is untagged
– The form of mux/demux on each port is changeable on
a packet-by-packet basis – quite amazing!
• on packet can come in w/o a VLAN tag requiring the switch to
forward it according to rules of its untagged VLAN setting
• another packet can come in with a VLAN tag and need to be
switched accordingly.
1/25/2005
26
User-plane capabilities
(to support CO internetworking)
• Cisco GSR
– “L3 MPLS” – map packets of a certain flow to an
MPLS tunnel.
– Ethernet over MPLS
• VLAN
• Port mapped
• VLAN rewrite
– This is simply a CO PS scenario where the label is changed.
With a VLAN, the same label is used on all links unlike in the
more generic CO PS where labels are only unique to a link
– With VLAN rewrite on the other side of a different type of
network, the VLAN ID is changed (i.e. label).
1/25/2005
27
User-plane capabilities
(to support CO internetworking)
• Cisco 15454 and Movaz box
– Can map all frames arriving on a port to a
SONET circuit or wavelength
• SDM ↔ SONET or WDM
• Unsure whether Ethernet cards are capable of
processing VLAN IDs or IP header fields to then
decide which ones to map to a certain SONET
circuit or wavelength
1/25/2005
28
Background
(what info does a switch/gateway have)
• OSPF (2328):
– Summary LSAs, Router LSAs, Network LSAs
– Summary LSAs sent by area border routers with
reachability information
• OSPF-TE (3630):
– TE LSAs – top-level TLV: Link TLV
• ccamp extensions for GMPLS:
– sub-TLVs that describe switching capability on link
identified in top-level Link TLV
1/25/2005
29
OSPF-TE (3630)
The following sub-TLVs of the Link TLV are defined:
1 - Link type (1 octet)
2 - Link ID (4 octets)
3 - Local interface IP address (4 octets)
4 - Remote interface IP address (4 octets)
5 - Traffic engineering metric (4 octets)
6 - Maximum bandwidth (4 octets)
7 - Maximum reservable bandwidth (4 octets)
8 - Unreserved bandwidth (32 octets)
9 - Administrative group (4 octets)
1/25/2005
30
ccamp extensions for GMPLS
Sub-TLV Type Length Name
11
14
15
16
1/25/2005
8
4
variable
variable
Link Local/Remote Identifiers
Link Protection Type
Interface Switching Capability Descriptor
Shared Risk Link Group
31
GSR capabilities and Link TLVs
• Cisco GSR is capable of
– “L3 MPLS” – mapping a flow at the IP layer to
an MPLS LSP
– Ethernet over MPLS:
• VLAN
• Port mapped
• VLAN rewrite – this is nothing but changing labels
– generically in CO PS networks the labels are unique only
to each link; which means they are mapped from link to
link on the end-to-end path.
1/25/2005
32
GSR capabilities and Link TLVs
• These capabilities of the GSRs got us wondering whether
in addition to Link TLVs in TE LSAs we need some way
of identifying the capabilities of the gateways
– e.g., whether it supports VLAN over MPLS in addition to L3
MPLS
• One answer:
– Don’t need another TLV
– The gateways need to “pretend” they are interconnected by logical
links and advertise the switching capability (i.e., the types of
multiplexing) available on these links
– If two LERs at the edge of an MPLS cloud can support VLAN
over MPLS then they advertise a direct logical link between the
LERs, which supports VLAN multiplexing
1/25/2005
33
Use routing data to ask for the right
type of connection
• By spreading multiplexing capabilities on these “pretend”
logical links, a gateway/switch can determine whether or
not there is an end-to-end path with a certain type of
multiplexing
• If the routing data is somehow wrong, a gateway/switch
should simply reject a call if it receives a Path request for a
certain type of connection that it does not support (e.g., a
request for a TDM circuit via a WDM switch or a request
for a VLAN connection to a gateway whose outgoing
logical links to other gateways on an MPLS cloud do not
support “VLAN over MPLS”
1/25/2005
34
Possible multiplexing schemes on the CO
internetwork, i.e., the outermost network
• Three possibilities
– SDM (Fiber switch capable)
– VLAN
– IP (Connection-oriented)
1/25/2005
35
Two points re. outermost network
• Presence of IP and Ethernet even with SDM
outermost network
• Forget hierarchy
1/25/2005
36
Point 1: Presence of IP and Ethernet
even with SDM outermost network
• Even when SDM is outermost network, user-data
payload is carried in IP datagrams encapsulated in
Ethernet frames
– Reason 1: Use socket API in application programming
– which means IP datagram encapsulation is a given.
– Reason 2: Ethernet is the common NIC for end hosts;
so Ethernet frame encapsulation is a given.
• Small overhead – hence ignored
1/25/2005
37
Point 2: Forget hierarchy
• Conventional thinking:
– SDM is at the lowest level of the hierarchy
– Common view:
• MPLS over SONET over WDM over fiber
• Contrary view here:
– SDM (aka) fiber is outermost network!
• Any “multiplexing/switching layer” can ride on
top of any other multiplexing/switching layer
– Just depends on network topology
1/25/2005
38
Scenarios
• Scenario 1: SDM-(VLAN)-(MPLS)-(VLAN)SDM
– No VLAN capability at end host NICs; but these NICs
are connected to Ethernet switches with VLAN cap.
– Gateways between VLAN and MPLS networks have
VLAN capability in Ethernet cards but these gateways
have no support to carry VLAN frames on MPLS LSPs
• Gateways issue OSPF-TE LSAs indicating GW↔GW
“pretend” links support FSC
• Also basic OSPF LSAs indicate availability of “pretend” links
allowing for CO IP to the outermost network (internetwork)
– Make outermost network call setup be SDM
1/25/2005
39
End-to-end CO: Scenario 1
SDM-(VLAN)-(MPLS)-(VLAN)-SDM
Routing info distribution phases
Network 1
GW2 is
a
gateway
VLSR
Network 2
VLSR GW1
VLSR
H
H1
Network 3
GW2
and
and
GW3 are GW4 are
gateway gateway
s
s
G
V
G
GW1
SW1
GW2
VLAN multiplexing
GW1’s
GW1’s
Link
LinkState
StateDatabase
Database
GW1’s
LSA
VLSR
M
G
SW2
GW3
MPLS multiplexing
Sw. Cap.
GW1-SW1
GW1-SW1
2
L2SCTDM
GW2
GW2
SW1:3.2-II.2
GW1-GW2
FSC/L2SC
2
L2SC
GW1-H1 GW2-GW3
3
FSC FSC/PSC-1
GW2
GW2
II.3
FSC SW1-GW2
2
L2SC
1/25/2005
GW3
GW3-GW4
FSC/L2SC
V
G
SW3
VLAN multiplexing
H2
GW4
GW2’s
LSA
GW2’s
LSA
SW1’s LSA
Type
Link
Link Sw. Cap.
Sw.Sw.
Cap.
Cap. Link
GW3 is
a
gateway
H
Type
Link
Router
Router
VLSR
VLSR
Link Link Link type
Type
SW1-GW2
SW1-GW2 2 2
Sw.Cap.
Cap.
Sw.
L2SC
L2SC
GW2-SW2
GW2-SW2 2 2
GW1-GW2
Pretend
PSC-1
PSC-1
FSC/L2SC
40
GW2-GW3
FSC/PSC-1
Pretend
End-to-end CO: Scenario 1
SDM-(VLAN)-(MPLS)-(VLAN)-SDM
Routing path precomputation phases
Network 1
VLSR
Network 2
VLSR
VLSR
Network 3
VLSR
VLSR
VLSR
H
H
H1
G
V
G
M
G
GW1
SW1
GW2
SW2
GW3
VLAN multiplexing
MPLS multiplexing
V
SW3
VLAN multiplexing
G
H2
GW4
Internetwork: SDM muxing based network
Outer Routing table
GW1’s LS database
Dest.
Next hop
Sw. Cap.
H2
GW2
FSC
Router
Link
Link type
Sw. Cap.
GW2
GW1-SW1
2
L2SC
GW2
GW2-SW2
2
PSC-1
GW2
GW2-GW3
Pretend
FSC
Dest.
Next hop
Sw. Cap.
GW21/25/2005
GW1-GW2
…
…
Pretend
FSC
GW2
SW1
41
L2SC
…
…
CSPF
Inner Routing table
End-to-end CO: Scenario 1
SDM-(VLAN)-(MPLS)-(VLAN)-SDM
Signaling phase
Network 1
PATH
VLSR
VLSR
Network 2
VLSR
Network 3
VLSR
VLSR
VLSR
RESV
H
H
H1
G
V
G
M
G
GW1
SW1
GW2
SW2
GW3
VLAN multiplexing
MPLS multiplexing
V
SW3
VLAN multiplexing
G
H2
GW4
Internetwork: SDM muxing based network
Path
Resv
Dest
BW
Sw. Stack
cap. of labels
LSP enc.
GPID
Ethernet? of GPID)
H1-GW1-GW2-GW3-GW4-H2
H1-GW1-GW2-GW3-GW4-H2
H2
Intserv
H2Tspec
MAC (know
FSC
to generateFiber
thisorbecause
Ethertype
GW1-SW1-GW2
GW1-SW1-GW2GW2
Intserv Tspec
GW2-SW2-GW3
GW2-SW2-GW3 (assumingGW3
Eth. links)
Intserv Tspec
1/25/2005
GW3-SW3-GW4
GW3-SW3-GW4GW4
Intserv Tspec
or packet?
GW2
L2SCMACEthernet
+ VLAN
ID VLAN? Ethertype
Packet? label
Ethernet?
GW3
PSC-1
MAC + MPLS
or packet?
GW4
L2SCMACEthernet
+ VLAN
ID VLAN?
Ethertype
42
Ethertype
End-to-end CO: Scenario 1
SDM-(VLAN)-(MPLS)-(VLAN)-SDM
User-plane: data flow phase
(MPLS network links are both Ethernet)
Network 1
Network 3
Network 2
VLSR
VLSR
VLSR
VLSR
H2 H2
VLSR
VLSR
Data
MAC IP
GW3 MPLS H2 H2
GW4 VLAN H2 H2
H2 H2
GW2
Data
Data
Data
HVLAN H2 H2 Data
MAC
Label
MAC
IP
MAC
1
ID
MAC
IP
MAC
IP
MAC
1 ID MAC IP
H1
G
V
G
M
G
GW1
SW1
GW2
SW2
GW3
VLAN multiplexing
MPLS multiplexing
V
SW3
VLAN multiplexing
G
H
H2
GW4
Internetwork: SDM muxing based network
1/25/2005
43
End-to-end CO: Scenario 1
SDM-(VLAN)-(MPLS)-(VLAN)-SDM
User-plane: data flow phase
(MPLS network links are both PPP)
Network 1
Network 3
Network 2
VLSR
VLSR
VLSR
VLSR
H2 H2
VLSR
VLSR
Data
MAC IP
PPP MPLS H2 H2
GW4 VLAN H2 H2
H2 H2
GW2
Data
Data
Data
HVLAN H2 H2 Data
header
Label
MAC
IP
MAC
1
ID
MAC
IP
MAC
IP
MAC
1 ID MAC IP
H1
G
V
G
M
G
GW1
SW1
GW2
SW2
GW3
VLAN multiplexing
MPLS multiplexing
V
SW3
VLAN multiplexing
G
H
H2
GW4
Internetwork: SDM muxing based network
1/25/2005
44
End-to-end CO: Scenario 1
SDM-(VLAN)-(MPLS)-(VLAN)-SDM
Signaling phase
MPLS network: first link is PPP and the second Ethernet
Network 1
PATH
VLSR
Network 2
VLSR
VLSR
Network 3
VLSR
VLSR
VLSR
RESV
H
H
H1
G
V
G
M
G
GW1
SW1
GW2
SW2
GW3
VLAN multiplexing
MPLS multiplexing
V
SW3
VLAN multiplexing
G
H2
GW4
Internetwork: SDM muxing based network
Path
Resv
Dest
BW
Stack ofLSP
labels
Sw. cap.
enc.
GPID
Fiber or
Ethernet?
H1-GW1-GW2-GW3-GW4-H2
H2 MAC (know
this
because of GPID)
H1-GW1-GW2-GW3-GW4-H2
H2
Intserv Tspec
FSC to generate
Ethertype
GW1-SW1-GW2
GW1-SW1-GW2
GW2
Intserv Tspec
GW2-SW2-GW3 (assuming
Eth. links)
GW2-SW2-GW3
GW3
Intserv Tspec
1/25/2005
GW3-SW3-GW4
GW3-SW3-GW4
GW4
Intserv Tspec
Ethernet
packet?ID
VLAN?
GW2 MAC
+ or
VLAN
L2SC
Ethertype
Ethernet?
GW3 MAC Packet?
+ MPLS
label
PSC-1
Ethertype
GW4
L2SC
Ethernet
packet?ID
VLAN?
MAC
+ or
VLAN
45
Ethertype
Scenarios contd.
• Scenario 2: SDM-(VLAN-(MPLS)-VLAN)-SDM
– No VLAN capability at end host NICs; but these NICs
are connected to Ethernet switches with VLAN cap.
– Gateways between VLAN and MPLS networks have
VLAN capability in Ethernet cards and these gateways
have support to carry VLAN frames on MPLS LSPs
• Gateways issue OSPF-TE LSAs indicating GW↔GW
“pretend” links support FSC and L2SC (VLAN)
• Also basic OSPF LSAs indicate availability of “pretend” links
allowing for CO IP to the outermost network (internetwork)
– Make outermost network call setup be SDM
1/25/2005
46
End-to-end CO: Scenario 2
SDM-(VLAN-(MPLS)-VLAN)-SDM
Routing info distribution phases
Network 1
GW2 is
a
gateway
VLSR
Network 2
VLSR GW1
VLSR
H
H1
GW2
and
and
GW3 are GW4 are
gateway gateway
s
s
G
V
G
GW1
SW1
GW2
VLAN multiplexing
Network 3
VLSR
GW3 is
a
gateway
H
M
G
SW2
GW3
MPLS multiplexing
VLSR
VLSR
V
H2
G
SW3
VLAN multiplexing
GW4
Internetwork: SDM muxing based network
SW1’s LSA
GW1’s
LSA
GW1’s
Link
State Database
Link
Router
GW1:H1
GW4
GW2
GW1-SW1
GW2
GW4
…
Link
Type
Link Sw. Cap. Sw. Cap.
GW1-SW1
3
FSC FSC/L2SC
GW1-GW4
SW1-GW2
L2SC
2
L2SC
SW1-GW2
GW2-SW2
GW4:H2
PSC-1
FSC
…
…
1/25/2005
Link
Type
GW2’s LSA
Sw. Cap.
Type
Sw. Cap.
SW1-GW2
Link
2Type
L2SCSw. Cap.
2
L2SC
GW2-SW2
GW1-GW2
Pretend
2
PSC-1/L2SC
FSC/L2SC
2
L2SC
GW2-GW3
Pretend
FSC/PSC-1/L2SC
47
End-to-end CO: Scenario 2
SDM-(VLAN-(MPLS)-VLAN)-SDM
Routing path precomputation phases
Network 1
VLSR
Network 2
VLSR
VLSR
Network 3
VLSR
VLSR
VLSR
H
H
H1
G
V
G
M
G
GW1
SW1
GW2
SW2
GW3
VLAN multiplexing
MPLS multiplexing
V
SW3
VLAN multiplexing
Internetwork: SDM muxing based network
GW1’s Link State Database
Router
Link
Sw. Cap.
GW4
GW1-GW4
FSC/L2SC
GW4
GW4:H2
FSC
GW2-GW3
FSC/L2SC/PSC-1
…
…
GW2
…
1/25/2005
CSPF
Outer
Intermediate
Inner
G
H2
GW4
Routing tables
Dest.
Next hop
Sw. Cap.
H2
GW4
FSC
Dest.
Next hop
Sw. Cap.
GW4
GW2
L2SC
Dest.
Next hop
GW2
SW1
Sw. Cap.
48
L2SC
End-to-end CO: Scenario 2
SDM-(VLAN-(MPLS)-VLAN)-SDM
Signaling phase
(MPLS network links are both Ethernet)
Network 1
PATH
VLSR
VLSR
Network 2
Network 3
VLSR
VLSR
VLSR
VLSR
RESV
H
H
H1
G
V
G
M
G
GW1
SW1
GW2
SW2
GW3
VLAN multiplexing
MPLS multiplexing
V
SW3
VLAN multiplexing
G
H2
GW4
Internetwork: SDM muxing based network
Path Resv
Dest
H1-GW1-GW4-H2
H1-GW1-GW4-H2
H2
GW1-SW1-GW2-GW3-SW3-GW4
GW4
GW1-SW1-GW2-GW3-SW3-GW4
GW2-SW2-GW3
GW2-SW2-GW3
1/25/2005
GW3
BW
Sw. caps
LSP enc.
Stack
of labels
GPID
Intserv
Tspec
FSC
Fiber of GPID)
Ethertype
H2 MAC
(know to generate
this because
?
L2SC + VLAN ID
?
GW2 MAC
Ethertype
IntservGW3
TspecMAC +PSC-1
Packetlabel Ethertype
VLAN ID +MPLS
49
End-to-end CO: Scenario 2
SDM-(VLAN-(MPLS)-VLAN)-SDM
User-plane: data flow phase
(MPLS network links are both Ethernet)
Network 1
Network 3
Network 2
VLSR
VLSR
VLSR
VLSR
H2 H2
VLSR
VLSR
Data
MAC IP
GW3 MPLSVLAN H2 H2 GW4 VLAN H2 H2
GW2
Data H2 H2 Data
HVLAN H2 H2MAC
Data Label 1 ID MAC IP Data
MAC
1
ID
MAC
IP
MAC
1 ID MAC IP
MAC IP
H1
G
V
G
M
G
GW1
SW1
GW2
SW2
GW3
VLAN multiplexing
MPLS multiplexing
V
SW3
VLAN multiplexing
G
H
H2
GW4
Internetwork: SDM muxing based network
1/25/2005
50
Scenarios contd.
• Scenario 3: VLAN-(MPLS)-VLAN
– VLAN capability at end host NICs and these NICs are
connected to Ethernet switches with VLAN cap.
– Gateways between VLAN and MPLS networks have
VLAN capability in Ethernet cards and these gateways
have support to carry VLAN frames on MPLS LSPs
• Gateways issue OSPF-TE LSAs indicating GW↔GW
“pretend” links support FSC and L2SC (VLAN)
• Also basic OSPF LSAs indicate availability of “pretend” links
allowing for CO IP to the outermost network (internetwork)
– Make outermost network call setup be VLAN
1/25/2005
51
End-to-end CO: Scenario 3
VLAN-(MPLS)-VLAN
Routing info distribution phases
Network 2
VLSR
VLSR GW3 is VLSR
GW2 is VLSR
VLSR
a
gateway
H
VLSR
a
gateway
H1
H
V
V
G
M
G
V
V
SW1
SW2
GW2
SW3
GW3
SW4
SW5
H2
MPLS multiplexing
VLAN multiplexing
GW2’s
GW2’s
Link
LSA
State
Database
GW2’s
Link
State
Database
Type
Sw. Cap.
GW2-SW3
GW3
SW3-GW3
2
PSC-1
PSC-1GW2-SW3
GW3
GW2-GW3
FSC/L2SC/PSC-1
2
PSC-1
GW2’s LSA
LSA
GW2’s
Link
Type
Link
Type Sw.
Sw.Cap.
Cap.
SW3-GW3
22
PSC-1
SW3-GW3
PSC-1
SW2-GW2
GW3
GW3-SW4
2
L2SC L2SC
SW3-GW3
GW3
GW3-SW4
L2SC
2
PSC-1
GW3-SW4
GW3-SW4
22
GW2-GW3
Pretend
Router
Link
Router
Type
Link
Sw.Sw.
Cap.Cap.
Link
Link Sw. Cap.
1/25/2005
…
…
GW2’s LSA
…
…
……
L2SC
52 L2SC
L2SC
End-to-end CO: Scenario 3
VLAN-(MPLS)-VLAN
Routing path precomputation phases
Network 2
VLSR
VLSR
VLSR
VLSR
VLSR
VLSR
H
H
H1
V
G
M
G
V
SW3
GW3
V
SW2
GW2
SW4
SW5
V
SW1
H2
MPLS multiplexing
VLAN multiplexing
GW2’s Link State Database
Router
Link
Sw. Cap.
GW3
GW2-GW3
FSC/L2SC/PSC-1
GW3
GW3-SW4
L2SC
…
…
…
1/25/2005
CSPF
Outer
Inner
Routing tables
Dest.
Next hop
Sw. Cap.
H2
GW3
FSC
Dest.
Next hop
GW3
SW3
Sw. Cap.
53PSC-1
End-to-end CO: Scenario 3
VLAN-(MPLS)-VLAN
Signaling phase
(MPLS network links are both Ethernet)
Network 2
PATH
VLSR
VLSR
VLSR
VLSR
VLSR
VLSR
RESV
H
H
H1
V
V
G
M
G
V
V
SW1
SW2
GW2
SW3
GW3
SW4
SW5
H2
MPLS multiplexing
VLAN multiplexing
Path
Resv
Dest
BW
H1-SW1-SW2-GW2-GW3-SW4-GW4H1-SW1-SW2-GW2-GW3H2
SW4-GW4-H2 H2
GW2-SW3-GW3
GW2-SW3-GW3
GW3
1/25/2005
Sw.Stack
caps of labels
LSP enc.
GPID
to generate this because
of Ethertype
GPID)
?H2 MAC (know
L2SC
?
Intserv Tspec
GW3
MAC + VLAN
ID
PSC-1
Packet
Ethertype
54
End-to-end CO: Scenario 3
VLAN-(MPLS)-VLAN
Signaling phase
(MPLS network links are both Ethernet)
Network 2
VLSR
GW2 VLAN H2 H2
Data
MAC 1 ID MAC IP
H
VLSR
SW1
VLSR
VLSR
VLSR
GW3 MPLSVLAN H2 H2 H2 VLAN H2 H2
Data
Data
MAC Label 1 ID MAC IP MAC 1 ID MAC IP
H1
V
VLSR
H
V
G
M
G
V
SW3
GW3
V
SW2
GW2
SW4
SW5
H2
MPLS multiplexing
VLAN multiplexing
1/25/2005
55
Scenarios contd.
• Scenario 4: VLAN-(SONET)-VLAN
– VLAN capability at end host NICs and these NICs are
connected to Ethernet switches with VLAN cap.
– Gateways between VLAN and SONET networks have
VLAN capability in Ethernet cards and these gateways
have support to carry VLAN frames on SONET circuits
• Gateways issue OSPF-TE LSAs indicating GW↔GW
“pretend” links support FSC and L2SC (VLAN)
• Also basic OSPF LSAs indicate availability of “pretend” links
allowing for CO IP to the outermost network (internetwork)
– Make outermost network call setup be VLAN
– See notes
1/25/2005
56
End-to-end CO: Scenario 4
VLAN-(SONET)-VLAN
Routing info distribution phases
Network 2
VLSR
VLSR GW3 is VLSR
a
gateway
H
VLSR
GW2 is VLSR
VLSR
a
gateway
H1
H
H2
V
V
G
M
G
V
V
SW1
SW2
GW2
SW3
GW3
SW4
SW5
SONET multiplexing
VLAN multiplexing
GW2’s
GW2’s
GW2’s
Link
Link
LSA
State
State
Database
Database
Router
Router
Link
GW2’s LSA
Type
Link
Link Sw. Cap.
Sw.Sw.
Cap.Cap.
Link
GW2’s
GW2’sLSA
LSA
Type
Sw. Cap.
Link
GW2-SW3
GW3
GW3
SW3-GW3
GW2-GW3
2
TDM TDM
FSC/TDM
GW2-SW3
2
TDM
SW3-GW3
22
SW2-GW2
GW3
GW3
GW3-SW4
GW3-SW4
2
L2SC L2SC
L2SC
SW3-GW3
2
TDM
GW3-SW4
22
1/25/2005
…
…
…
…
……
GW2-GW3
Type
Type Sw.Sw.
Cap.
Cap.
Pretend
TDM
TDM
L2SC
L2SC
57
FSC/TDM
End-to-end CO: Scenario 4
VLAN-(SONET)-VLAN
Routing protocol and path precomputation phases
Network 2
VLSR
VLSR
VLSR
VLSR
VLSR
VLSR
H
H
H1
V
G
M
G
V
SW3
GW3
V
SW2
GW2
SW4
SW5
V
SW1
H2
SONET multiplexing
VLAN multiplexing
GW2’s Link State Database
Router
Link
Sw. Cap.
GW3
GW2-GW3
FSC/TDM
GW3
GW3-SW4
L2SC
…
…
…
1/25/2005
CSPF
Outer
Inner
Routing tables
Dest.
Next hop
Sw. Cap.
H2
GW3
FSC
Dest.
Next hop
GW3
SW3
Sw. Cap.
58TDM
End-to-end CO: Scenario 4
VLAN-(SONET)-VLAN
Signaling phase
Network 2
PATH
VLSR
VLSR
VLSR
VLSR
VLSR
VLSR
RESV
H
H
H1
V
V
G
S
G
V
V
SW1
SW2
GW2
SW3
GW3
SW4
SW5
H2
SONET multiplexing
VLAN multiplexing
Path
Dest
Resv
BW
H1-SW1-SW2-GW2H2
?
H1-SW1-SW2-GW2-GW3-SW4GW3-SW4-GW4-H2 GW4-H2
GW2-SW3-GW3
GW3
GW2-SW3-GW3
1/25/2005
Sw. Stack
caps of labels
LSP enc.
GPID
L2SC to generate this
? because of
Ethertype
H2 MAC (know
GPID)
SONET Tspec GW3TDM
SONET/SDH
SONET label
+ VLAN ID SONET/SDH
59
End-to-end CO: Scenario 4
VLAN-(SONET)-VLAN
User-plane: data flow phase
Network 2
VLSR
VLSR
VLSR
VLSR
GW2 VLAN H2 VLSR
H2
Data
MAC 1 ID MAC IP
SONETVLAN H2 H2
H2 VLAN H2 H2
Data
Data
H
frame 1 ID MAC IP
MAC 1 ID MAC IP
H1
V
V
G
SW1
SW2
GW2
VLAN multiplexing
1/25/2005
S
G
SW3
GW3
SONET multiplexing
V
SW4
VLAN multiplexing
VLSR
H
H2
V
SW5
60
For each scenario, answer the
following questions
1.
Routing protocol and path pre-computation phase:
•
2.
What should have been advertised by OSPF-TE and what
computations should have been run by CSPF modules?
Signaling phase:
•
What types of objects are used in Path messages for the five
parameters and what values are set in the key fields of these
objects?
What labels are carried in the Resv messages? Which interface’s
MAC address is necessary at sender?
•
3.
User-plane:
•
1/25/2005
Packet formats on each interface
61
Why end host needs CO reachability
information with type of CO service (slide i)
• In CL IP networks:
– default setting: use IP subnet address to
determine whether destination is directly
reachable or not?
– this allows sending end host to issue an ARP
with IP address of destination host or IP address
of gateway (typically just one – since there is
only one type of internetwork CL service, aka
IP)
1/25/2005
62
Why end host needs CO reachability
information with type of CO service (slide ii)
• If the sending host has a manually set entry in its IP routing
table for the destination host which is on a different subnet
as well as an entry in the ARP table giving the MAC
address of the destination (H2)
– It can generate a frame with destination MAC address = H2 and
destination IP address = H2
– The default gateway will not intercept the packet in some sort of
proxy mode and relay it to the destination
– This is an application of the “end-to-end argument”
– If the gateway did intercept such a packet, it becomes more like
Intelligent Networks
– What will happen is that the default gateway will not accept the
packet since the destination MAC address does not match it’s own
interface’s MAC address. Therefore the packet will just be dropped
1/25/2005
63
Why end host needs CO reachability
information with type of CO service (slide iii)
• Applying similar reasoning
– it is the responsibility of the end host to generate a Path
message requesting the “right” type of connection to a
destination, i.e., one that is indeed available.
– if such a connection is not possible, the call should be
rejected
• Sending end host has three options for the type of
connection it can request
– SDM
– VLAN
– CO IP
1/25/2005
64
Why end host needs CO reachability
information with type of CO service (slide iv)
• This concept of the gateway not automatically changing
the type of Path request holds at each hop.
• Example:
– In scenario 1, if the VLAN-MPLS GW2 had not announced
availability of SDM multiplexing on its pretend link to the far-end
GW on the MPLS network, the SDM-VLAN GW1 would not have
issued the Path request of the SDM variety.
– By having OSPF-TE LSAs for pretend links, we can use the endto-end argument in CO networks
– Without these LSAs, gateways would need to automatically
convert the type of requests – makes it more IN like.
1/25/2005
65
Why end host needs CO reachability
information with type of CO service (slide v)
• Implication
– End hosts need to keep a CO routing table
– How is this information learned at end hosts
– LMP? Since end hosts don’t run OSPF
Destination IP addr
(subnet or host)
1/25/2005
Gateway
(next-hop)
Type of connection
(SDM, VLAN, CO IP)
66
CO internetworking
•
•
•
•
Terminology, questions
Problem description
Take a cue from CL internetworking
CO internetworking CHEETAH scenario (simple)
– Network-by-network setup
– Continued setup
• CO internetworking: complex scenarios with
MPLS, VLANs, SONET, WDM
 Partial CO segments intermixed with CL segments
• Research problems, key ideas, conclusions
1/25/2005
67
Partial Connection Oriented: Scenario 1
Ethernet-MPLS-Ethernet Scenario
Routing protocol and path precomputation phases
VLSR
H1
H
I.1
E
E
Network 3
Network 2
Network 1
I.2
VLSR
3.1
G
GW1
Ethernet packet-based
multiplexing (E1)
3.2
II.2
M
G
SW3
(MPLS)
H
II.3
E
GW2
E
H2
Ethernet packet-based
multiplexing (E2)
IP packet-based multiplexing
H2
GW1
End-host A’s
routing table
1/25/2005
Link
Sw. Cap.
Link
Sw. Cap.
GW1-GW2
PSC-1
GW1-GW2
PSC-1
GW2’s advertised link
TLVs
GW3’s advertised link
TLVs
68
Partial Connection Oriented: Scenario 1
Ethernet-MPLS-Ethernet Scenario
Signaling phase
PATH
VLSR
tagging
H1
Network 3
Network 2
Network 1
VLSR
untagging
RESV
H
I.1
E
E
I.2
G
GW1
Ethernet packet-based
multiplexing (E1)
3.1
3.2
M
SW3
(MPLS)
II.2
H
II.3
G
GW2
E
E
H2
Ethernet packet-based
multiplexing (E2)
Ethernet packet-based multiplexing
H2
GW1
End-host A’s
routing table
Path
Resv Dest
H1-GW1-GW2-H2
H1-SW2-GW2-H2
H2
1/25/2005
GW2-SW3-GW3
GW1-SW3-GW2
GW3
BW
Stack
Sw.
capsof labels
LSP enc.
GPID
H2 MAC
to generate this Packet
because of GPID)
Intserv
Tspec (knowPSC-1
Ethertype
Intserv Tspec
GW2
MAC + MPLSPacket
label
PSC-1
69
Ethertype
Partial Connection Oriented: Scenario 1
Ethernet-MPLS-Ethernet Scenario
User-plane: data flow phase
(MPLS network links are both Ethernet)
VLSR
GW1 H2
Data
MAC IP
H1
I.1
E
E
Ethernet packet-based
multiplexing (E1)
1/25/2005
VLSR
GW2 MPLS H2
Data
MAC Label IP
I.2 3.1
H
Network 3
Network 2
Network 1
G
GW1
3.2
M
SW3
(MPLS)
H2 H2
Data
II.2
MAC
IP II.3
G
GW2
H
E
E
H2
Ethernet packet-based
multiplexing (E2)
70
Partial Connection Oriented: Scenario 2
Ethernet-SONET-Ethernet Scenario
Routing protocol and path precomputation phases
Network 3
Network 2
Network 1
VLSR
H1
H
I.1
E
E
I.2
VLSR
3.1
G
GW1
Ethernet packet-based
multiplexing (E1)
3.2
II.2
M
G
SW3
(SONET)
H
II.3
E
GW2
E
H2
Ethernet packet-based
multiplexing (E2)
Ethernet packet-based multiplexing
H2
GW1
End-host A’s
routing table
1/25/2005
Link
Sw. Cap.
Link
Sw. Cap.
GW1-GW2
TDM
GW1-GW2
TDM
GW2’s advertised link
TLVs
GW3’s advertised link
TLVs
71
Partial Connection Oriented: Scenario 2
Ethernet-SONET-Ethernet Scenario
Signaling phase
PATH
VLSR
tagging
H1
Network 3
Network 2
Network 1
VLSR
untagging
RESV
H
I.1
E
E
I.2
G
GW1
Ethernet packet-based
multiplexing (E1)
3.1
3.2
M
SW3
(SONET)
II.2
H
II.3
G
GW2
E
E
H2
Ethernet packet-based
multiplexing (E2)
Ethernet packet-based multiplexing
H2
GW1
End-host A’s
routing table
Path
Resv Dest
H1-GW1-GW2-H2
H1-SW2-GW2-H2
H2
1/25/2005 GW1-SW3-GW2
GW1-SW3-GW2
GW3
BW
Stack
Sw.
capsof labels
LSP enc.
GPID
H2 MAC
to generate this Packet
because of GPID)
Intserv
Tspec (knowPSC-1
Ethertype
SONET Tspec
GW2
label
TDMSONETSONET/SDH
72
SONET/SDH
Partial Connection Oriented: Scenario 2
Ethernet-SONET-Ethernet Scenario
User-plane: data flow phase
VLSR
GW1 H2
Data
MAC IP
H1
I.1
E
E
Ethernet packet-based
multiplexing (E1)
1/25/2005
VLSR
SONET H2 H2
Data
frame MAC IP
I.2 3.1
H
Network 3
Network 2
Network 1
G
GW1
3.2
M
SW3
(MPLS)
H2 H2
Data
II.2
MAC
IP II.3
G
GW2
H
E
E
H2
Ethernet packet-based
multiplexing (E2)
73
CO internetworking
(intra-domain + inter-layer)
•
•
•
•
Terminology, questions
Problem description
Take a cue from CL internetworking
CO internetworking CHEETAH scenario (simple)
– Network-by-network setup
– Continued setup
• CO internetworking: complex scenarios with MPLS,
VLANs, SONET, WDM
• Partial CO segments intermixed with CL segments
 Research problems, key ideas, conclusions
1/25/2005
Malathi Veeraraghavan, Zhanxiang Huang, Xuan Zheng
{mv5g, zh4c, xuan}@virginia.edu
74
Nov. 25, 2004
Research vs. eng. problems
• Problem statement
– How to create connections (rate-guaranteed allocations)
across CO networks that support different types of
multiplexing?
• Mostly engineering problems
– What type of Path message objects to use, and what
values to use for the fields in these objects?
– How to declare “pretend” links to allow for path
computation or next-hop
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75
“Pretend” links
G
GW2
G
SW3
SW2
Path
GW3
SW4
M
M
M
G
GW1
OSPF
•
M
M
SW1
MPLS mux.
SW5
G
G
GW4
GW5
How many pretend links should be advertised to outside this network?
–
N(N-1)/2 links, where N is number of GWs, e.g.,GW1↔GW2; GW1↔GW3.....
•
What is the capacity for each of these pretend links? How should gateway-to-switch and switch-to-switch link capacity be
divided between the pretend links before advertising – estimates?
•
Actual routing of connections to make these pretend links real can be changed during setup.
•
Switching capabilities on these links are easy – if GW1 supports VLAN over MPLS as well as Layer 3 MPLS, just advertise
1/25/2005
76
L2SC, SDM and whatever allows for 2205 RSVP (which is CO IP)
Is there a research problem?
•
First consider the research problems in this
whole area of routing/signaling/user-plane
protocols – in homogeneous networks
–
There are two problems when deconstructed (i.e,
context is removed)
1.
2.
1/25/2005
routing problem deconstructs to the constrained shortest path
computation in a graph problem
signaling – main aspect is bandwidth management – CAC;
so here the research problem is how to bandwidth share?
Accept/reject a call or provide less BW than asked for?
Classes of service; fairness traded off against utilization;
ULGM sharing; how to set UL and GMs?
77
CSPF routing deconstructed problem
in homogeneous network
Link weight Available BW
2, 30Mbps
a
b
1, 150Mbps
d
5, 100Mbps
2, 50Mbps
c
•
•
•
•
1, 10Mbps
f
1, 500Mbps 1, 50Mbps
1, 50Mbps
e
Example constraint: bandwidth
Problem: find SP from a-f with min. BW = 30Mbps
Answer: a-b-c-e-f: path weight = 2 + 5 + 1 + 1 = 9
Path a-b-d-f is shortest path with path weight = 2+1+1 = 4, but BW available is only
1/25/2005
78
10Mbps, less than the required 30Mbps
How does the addition of the heterogeneity
dimension affect these two research problems?
Routing problem
Available BW Crossconnect granularity
e.g., WDM switch
1Mbps
Link weight
1, 3200Gbps
2, 30Mbps
b
10Gbps
1, 8000Gbps
a
d
5, 100Mbps
f
1, 10Gbps
2, 10Gbps
1, 10Gbps
e.g., SONET switch
e
c
1Mbps
e.g., MPLS switch
•
•
•
1, 2.5Gbps
•
•
51Mbps
New constraint: node crossconnect granularity
Problem: find SP from a-f with min. BW = 30Mbps
Answer: a-b-d-f: path weight = 2 + 1 + 1 = 4, and 30Mbps is available, but it needs the
setup of a 10Gbps circuit on b-d-f before 30Mbps can be assigned on this logical link.
If1/25/2005
the rule had been to tie up minimum extra bandwidth, then path would be a-b-c-e-f
79
Or split connection on small-granularity paths
Bandwidth sharing deconstructed problem
in homogeneous network
Request for 30Mbps connection
2, 30Mbps
a
b
1, 150Mbps
d
5, 100Mbps
2, 50Mbps
c
1, 10Mbps
f
1, 500Mbps 1, 50Mbps
1, 50Mbps
e
• Problem: Should node b accept the call, reject the call or assign it some
BW lower than the requested 30Mbps
– Simple Complete Sharing (CS) algorithm would say yes!
– But from a fairness perspective (short-duration vs. long-duration, short-path
vs. long-path), node b may reject the call or give a lower BW level
1/25/2005
• Added dimension: to split call on different routes
80
Bandwidth sharing deconstructed problem
in heterogeneous network
Request for 30Mbps connection
1Mbps
2, 30Mbps
a
b
1, 150Mbps
10Gbps
d
5, 100Mbps
2, 50Mbps
c
1, 10Mbps
1, 50Mbps
f
1, 500Mbps 1, 50Mbps
e
51Mbps
1Mbps
• Problem:
– Tradeoff of fairness and utilization becomes more
difficult when these crossconnect granularities are
1/25/2005 considered
81
Hop-by-hop vs. source routing
• I think both can be supported even for QoSbased routing
• Industry seems to lean toward source
routing
1/25/2005
82
Key ideas
• Use nested LSPs, each of a uniform
multiplexing type (aka switching capability)
• Advertise “pretend links” to enable other
gateways/switches to determine whether
they can set up an LSP of a certain type
1/25/2005
83
Conclusions
• Is there a protocol to share reachability data from nearest
CO switch/gateway to end host – use of LMP?
• Pretend links – how do nodes automatically recognize need
to report these?
– From OSPF-TE LSAs on interface switching capabilities, easy to
recognize gateways from switches
– A gateway reports a pretend link to each other gateway that it can
reach with one form of multiplexing
– Report current available BW as minimum available BW to each
gateway (ignore the fact that if a connection got set up to one
gateway, the available BWs drop and hence available BW to
another gateway will also drop)
1/25/2005
84
Conclusions for my original problem
• What should OCS do?
– Useful to bring back MAC address of
destination end host?
– Determine type of CO path available?
1/25/2005
85
What software modules need to be developed and deployed
e.g., SDM-(VLAN)-(MPLS)-(VLAN)-SDM
Serves as an RSVP-TE client at an
“end host” for this connection
OSPF LSA
Pretend
link advertiser
PATH
H
Pretend
link advertiser
Network 1
Pretend link
signaling module
Pretend link
signaling module
VLAN
VLSR
VLAN
VLSR
G
V
OSPF-TE
H1
GW1
Network 2
RSVP-TE
Pretend
link advertiser
Pretend link
signaling module
Network 3
VLSR
VLAN multiplexing
Cisco
GSR
Pretend link
signaling module
Update
conn.
table
RESV
H
OSPF-TE
M
RSVP-TE
V
SW2
SW1
Pretend
link advertiser
SW3
MPLS multiplexing GW3 VLAN multiplexing
G
H2
GW4
Internetwork: SDM muxing based network
Identify what
functionality each
gateway box and
custom-build gateway
GMPLS engine for that
box. Leverage software
1/25/2005in box.
implemented
See next slide for functional description of pretend link
advertiser and pretend link signaling module.
A Cisco GSR has
• RSVP-TE software as an end client, i.e., an MPLS LER
• RSVP-TE
86
Software for gateways
•
•
Pretend link advertiser:one per gateway - reads OSPF-TE database, recognize from
interfaces on all switches in network 2 that node GW3 is a gateway (links with multiple
switching capabilities); this means a pretend link should be advertised between these
two gateways. Determine what switching capabilities and rates to advertise for this
pretend link based on user-plane gateway capabilities of the box. The pretend links
should not be written into the connectivity table of the nodes unless there is software in
the nodes to handle these links differently from regular links.
Pretend-link signaling module: one per-gateway; if gateway has no RSVP-TE LER
(edge) engine to act like an end host client RSVP-TE, then it serves this functionality for
the gateway. If the gateway does have this built-in functionality, it simply serves to hold
up Path messages headed for the pretend links and invoke the RSVP-TE client software
through a CLI/TL1 command to initiate call setup. Thus, it receives RSVP-TE
messages, determines if it requires pretend link setup, then issues commands to initiate
the set up of the pretend link if not already setup. Then if the box has ability to integrate
the newly setup LSP as a FA -LSP, then it transparently passes the SDM RSVP-TE path
setup message to the RSVP-TE signaling module built into the gateway. The latter will
make the GW2 RSVP-TE signaling module handle it and send one to the GW3 RSVPTE signaling module; these modules act as the RSVP-TE end host clients for the intranetwork connection or as the external trigger for the RSVP-TE client built into the node
as an end host client (e.g., the GSR).
1/25/2005
87
End host first CO node discovery
• Define a protocol for end host software to broadcast a
discover – see if DHCP can be used augmented with usage
of some obscure field.
• Get multiple replies of which nodes have CO capability.
• Copy routing data from these nodes to know which IP
addresses are reachable through what form of CO network:
SDM, VLAN or IP.
• Need to deploy end host software for this purpose as well
as software external to CO nodes to respond to end hosts
queries.
• Limit this to an enterprise. If enterprise doesn’t purchase
CO service, individual end hosts cannot. So the DHCP
discovery of CO capability only spreads up to the WAN
access router.
1/25/2005
88
MAC address software?
• If sending RSVP-TE client at end host asks for SDM or
VLAN call with GPID as Ethernet, then receiving RSVPTE client at end host responds with MAC address of itself
in stacked label.
– Question: can Resv message processing at switches simply pass
this along?
• If sending RSVP-TE client at end host asks for CO IP call
(2205), then do not return MAC address.
• Software needed only at end hosts to handle MAC issue,
provided intermediate switches simply pass on higher
levels of label stacks.
• Test with SN16000 and Cisco GSR.
1/25/2005
89
• Test RSVP 2205 set up with GSR.