Transcript Document

GMPLS networks and optical
network testbeds
Malathi Veeraraghavan
Professor
Charles L. Brown Dept. of Electrical & Computer Engineering
University of Virginia
[email protected]
Tutorial at ICACT09
Feb. 2009
GMPLS: Generalized MultiProtocol Label Switched networks
(MPLS, SONET, WDM, SDM, VLAN)
1
Outline
• Principles
– Different types of connection-oriented
networks
• Technologies
– Single network
– Internetworking
• Usage
– Commercial networks
– Research & Education Networks (REN)
2
Principles
• Types of switches and networks
• Bandwidth sharing modes
– TCP in connectionless (IP) networks
– Immediate-request and book-ahead
modes in connection-oriented networks
3
Types of switches
Multiplexing technique on
data-plane links
Admission
control in
control plane?
Circuit
Packet switch (PS)
switch (CS) - header based
- position
based
(port, time,
lambda)
Connectionless (CL)
- no admission control
Not an
option
e.g., Ethernet
Connection-oriented (CO)
- admission control
e.g.,
telephone
SONET
WDM
Virtual-circuit
e.g., MPLS, ATM
4
Types of networks
Support function Addressing
(in data or
control
Network
plane?)
type
Routing
Signaling
Connectionless (CL) Data plane


Circuit Switched
(CS)
Control plane


Virtual circuit
(VC)
Control plane


Connection-oriented
5
How is bandwidth shared on a connectionless
packet-switched network?
• Pre-1988 IP network:
– Just send data without reservations or any mechanism to
adjust rates  congestion collapses!
• Van Jacobson's 1988 contribution:
– Added congestion control to TCP
– Sending TCP adjusts rate
– Advantages:
• Proportional fairness
• High utilization
– Disadvantages:
• No rate guarantees
• No temporal fairness (job seniority)
6
TCP throughput
1
B
RTT
•
•
•
•
•
•
•
•
2bp
3bp
 T0 min(1,3
) p (1  32 p 2 )
3
8
B: Throughput in congestion-avoidance phase
RTT: Round-trip time
b: an ACK is sent every b segments (b is typically 2)
p: packet loss rate on path
T0: initial retransmission time out in a sequence of retries
Effective rate = min (r,B)
r: bottleneck link rate
Padhye, Firoui, Towsley, Kurose, ACM Sigcomm 98 paper
7
TCP throughput
Case
Input parameters
Packet loss rate
Case 1
0.0001
Bottleneck link rate
Round-trip delay
0.1ms
82.25
Case 2
5ms
89.45
Case 3
50ms
396.5
0.1ms
8.25
Case 5
5ms
39.6
Case 6
50ms
395.7
0.1ms
82.93
5ms
135.4
50ms
1293
0.1ms
8.64
Case 11
5ms
129.4
Case 12
50ms
1287
0.1ms
92.41
5ms
471.7
50ms
4417
0.1ms
12.43
Case 17
5ms
441.7
Case 18
50ms
4387
Case 4
Case 7
100 Mb/s
Mean transfer delay
for a 1GB file (s)
1Gbps
0.001
Case 8
100
Mbps
Case 9
Case 10
Case 13
Case 14
1Gbps
0.01
100
Mbps
Case 15
Case 16
1Gbps
~21Mbps
~2Mbps
8
Bandwidth sharing in circuit networks
(immediate-request mode)
• Key difference:
– Admission control
– Intrinsic to circuit networks: position based mux
• Send a call setup request:
– if requested bandwidth is available, it is
allocated to the call
– if not, the call is blocked (rejected)
• M/G/m/m model:
– m: number of circuits
9
ErlangB formula



Pb 
: offered traffic load in Erlangs
: call arrival rate
1/: mean call holding time
m: number of circuits
Pb: call blocking probability
ub: utilization
 m / m!
m k
  / k!
k 0
(1  Pb )  
ub 
m
For a 1% call blocking probability, i.e., Pb = 0.01

1
10
100
m
ua
4
17
117
24.8%
58.2%
84.6%
If m is small, high
utilization can only be
achieved along with high
call blocking probability
10
Bandwidth sharing mechanisms
in CO networks
Needed if per-call
Bandwidth sharing mechanisms
circuit rate is a large
fraction of link capacity
(e.g., 1Gbps circuits on a
10Gbps link, m = 10)
Book-ahead
Immediate-request
call duration specified
BA-n/BA-First
session-type requests
BA-n
Users specify a set of
call-initiation time
options
unspecified call duration
VBDS
(Varying-Bandwidth Delayed Start)
BA-First
data-type requests
Users are given first
available timeslot
X. Zhu, Ph.D. Thesis, UVA, http://www.ece.virginia.edu/mv/html-files/students.html
11
Comparison of Immediate-Request (IR)
and Book-Ahead (BA) schemes
• Example
– To achieve a 90% utilization
with a call blocking probability
less than 10%
• BA-First schemes are needed
when m < 59
– To achieve a 90% utilization
with a call blocking probability
less than 20%
• BA-First schemes are needed
when m < 32
U: utilization
K: number of time periods in
advance-reservation window
IR m=10, U = 80%: PB = 23.6%
m=100, U = 80%: PB = 0.4%
BA m=10, K=10, U = 80%: PB = 0.4%
12
Virtual circuit (VC) networks
Bandwidth sharing
more complex, but
better utilization
PLUS service
guarantees
Call Admission Control
Needed in circuit
networks
Scheduling
(example: weighted fair queueing)
Traffic shaping/policing
(example: leaky-bucket algorithm)
Two additional
dimensions
in VC networks
13
Outline
• Principles
– Different types of connection-oriented
networks
Technologies
– Single network
– Internetworking
• Usage
– Commercial networks
– Research & Education Networks (REN)
14
Technologies
• GMPLS networks
 Data-(user-) plane protocols
• packet-switched: MPLS, VLAN Ethernet
• circuit-switched: SONET/SDH, WDM, SDM (space div. mux)
– Control-plane protocols:
• RSVP-TE: signaling protocol
• OSPF-TE: routing protocol
• LMP: link management protocol
• Internetworking
– GFP, VCAT, LCAS for SONET/SDH
– PWE3 for MPLS networks
– Digital wrapper for OTN
15
Multiprotocol label switching
(MPLS)
MPLS Header
Label Value
20 Bits
CoS S
3
1
TTL
8
• MPLS Header:
– Label Value: Label used to identify the virtual circuit
– Class of Service (CoS): Experimental field, Used for QoS
support
– S: Identifies the bottom of the label stack
– TTL: Time-To-Live value
• Virtual circuits: Label Switched Path (LSP)
IEEE 802.1Q Ethernet VLAN
new fields
Dest. MAC Source MAC
TPID TCI Type
Address
Address
/Len
Data
FCS
FCS: Frame
Check
Sequence
VLAN Tag
User
802.1Q Tag Type
CFI
Priority
2 Bytes
3 Bits
1 Bit
VLAN ID
12 Bits
VLAN Tag Fields
• Tag Protocol Identifier (TPID)
– 802.1Q Tag Protocol Type – set to 0x8100 to identify the
frame as a tagged frame
• Tag Control Information (TCI)
– User Priority
• As defined in 802.1p, 3 bits represent eight priority levels
– CFI
• Canonical Format Indicator, set to indicate the presence of
an Embedded-RIF
– VLAN ID
• Uniquely identifies the frame's VLAN
SONET/SDH rates
(number is the multiplier)
Example: STS-48 frame has 48 x 90 columns in 125 s
STS-1: 90 columns by 9 rows in 125 s
19
Tanenbaum
Optical transport networks (OTN)
• G. 872 layers
– OTS: Optical Transmission Section
– OMS: Optical Multiplex Section
– OCh: Optical Channel
• G.709:
– Technique for mapping client signals onto
the Optical Channel via layers:
• OTU: Optical Channel Transport Unit, and
• ODU: Optical Channel Data Unit
20
Layers within an OTN
21
Courtesy: T. Walker's tutorial
OTN Hierarchy
Low layer
Higher layers
• Electrical domain:
– OTU: Optical Channel Transport Unit
– ODU: Optical Channel Data Unit
– OPU: Optical Channel Payload Unit
Courtesy: T. Walker's tutorial
22
G. 709 Optical Channel frame structure
(digital wrapper)
OCh overhead
OCh payload
FEC
• Optical channel (OCh) overhead: support operations,
administration, and maintenance functions
• OCh payload: can be STM-N, ATM, IP, Ethernet, GFP
frames, OTN ODUk, etc.
• FEC: Reed-Solomon RS(255, 239) code recommended;
roughly introduces a 6.7% overhead
• Frame size: 4 rows of 4080 bytes
• Frame period:
– OTU1 – 48.971 μs (payload data rate: roughly 2.488 Gbps )
– OTU2 – 12.191 μs (payload data rate: roughly 9.995 Gbps )
– OTU3 – 3.035 μs (payload data rate: roughly 40.15 Gbps )23
Technologies
• GMPLS networks
– Data-(user-) plane protocols
• packet-switched: MPLS, VLAN Ethernet, Intserv IP
• circuit-switched: SONET/SDH, WDM, SDM
– Control-plane protocols:
 RSVP-TE: signaling protocol
• OSPF-TE: routing protocol
• LMP: link management protocol
• Internetworking
– GFP, VCAT, LCAS for SONET/SDH
– PWE3 for MPLS networks
– Digital wrapper for OTN
24
The evolution of
Resource reSerVation Protocol (RSVP)
• RSVP (RFC2205, 1997)
• RSVP-TE (RFC 3209, 2001)
• RSVP-TE GMPLS Extension (RFC 3471,
3473, 2003)
• RSVP-TE GMPLS Extension for
SONET/SDH (RFC 3946, 2004, RFC
4606, 2006)
25
Purpose of signaling
(needed only in CO networks)
• Functions:
– Call setup:
• Route selection
• Admission control: sufficient bandwidth?
• Switch fabric configuration of each switch
– recall position based multiplexing
– Call release
• release bandwidth for use by others
26
Circuit-switched networks
Phase 1: Routing protocol exchanges
+ routing table precomputation
II
Host
I-A
I
Dest.
Next hop
III-*
IV
Dest.
Next hop
III-B
III-C
III-B
III-C
Host
III-B
III
IV
V
Dest.
Next hop
III-*
III
Host
III-C
• Routing protocols exchange:
– topology
– address reachability
– loading conditions
27
Circuit-switched networks
Phase 2: Signaling for call setup
Connection setup
(Dest: III-B;
BW: OC1;
Timeslot: a, 1)
II
a
b
Host
I-A
a
I
III
c
b
d
c
Routing
table
Dest.
Next hop
III-*
IV
IV
a
d
Host
III-B
b
c
V
Connection setup actions at each switch on the path:
1.
2.
3.
4.
5.
6.
Parse message to extract parameter values
Lookup routing table for next hop to reach destination
Read and update CAC (Connection Admission Control)
table
Select timeslots on output port
Configure switch fabric: write entry into timeslot
mapping table
Construct setup message to send to next hop
28
Circuit-switched networks
Phase 2: Signaling for call setup
Connection setup
(Dest: III-B;
BW: OC1;
Timeslot: a, 1)
II
b
a
a
Host
I-A
I
c
Connection
setup
b
III
d
c
Routing
table
CAC
table
Dest.
Next hop
III-*
IV
a
Interface (Port);
Next hop Capacity; Avail timeslots
IV
Timeslot
mapping table
c; OC12; 1, 4, 5
INPUT
Port /Timeslot
a/1
OUTPUT
Port/Timeslot
IV
d
Host
III-B
b
c
V
Connection setup actions at each switch on the path:
1. Parse message to extract parameter values
2. Lookup routing table for next hop to reach destination
3. Read and update CAC (Connection Admission Control)
table
4. Select timeslots on output port
5. Configure switch fabric: write entry into timeslot
mapping table
6. Construct setup message to send to next hop
c/1
Update to remove timeslot 1
from available list
29
Circuit-switched networks
Phase 2: Signaling for call setup
II
b
Host
I-A
a
a
I
c
b
Connection
setup
d
c
Connection setup
(Dest: III-B;
BW: OC1;
Timeslot: a, 1)
Time slot
could be different
on each hop
IV
a
III
Host
III-B
b
c
V
d
INPUT
OUTPUT
Port /Timeslot Port/Timeslot
a/1
c/2
Perform same set of 6 connection setup steps at switch IV
write timeslot mapping table entry, update CAC table and
send connection setup message to the next hop
30
Circuit-switched networks
Phase 2: Signaling for call setup
INPUT
OUTPUT
Port /Timeslot Port/Timeslot
II
d/2
b
Host
I-A
a
a
I
b/1
c
b
Connection
setup
d
c
a
IV
III
d
Host
III-B
b
c
V
Connection
setup
Circuit setup
complete
Perform same set of 6 connection setup steps at switch III
Reverse setup-confirmation messages typically sent
from destination through switches to source host
31
Circuit-switched networks
Phase 3: User-data flow
1
IN
OUT
Port /Timeslot Port/Timeslot
2
II
b
Host
I-A
1
d/2
2
1
2
a
I
b
d
c
a
IN
OUT
Port /Timeslot Port/Timeslot
a/1
c/1
a
III
c
IV
d
b/1
b
c
1
2
Host
III-B
V
IN
OUT
Port /Timeslot Port/Timeslot
a/1
c/2
• Bits arriving at switch I on time slot 1 at port a
are switched to time slot 1 of port c
32
Release procedure
• When a communication session ends,
there is a hop-by-hop release
procedure (similar to the setup
procedure) to release
timeslots/wavelengths for use by new
calls
33
RSVP messages and parameters
• Messages:
– Setup: Path (forward) and Resv (reverse)
– Release: PathTear, ResvTear
• Parameters
– Destination: SESSION object
– Bandwidth: Sender Tspec object or SONET/SDH Tspec
– Timeslot/Wavelength:
• Generalized LABEL for ports, wavelengths
• SUKLM label for SONET/SDH
• Only supports immediate-request circuits/virtual
circuits
– No time-dimension parameters for book-ahead
34
Explicit Route Object (ERO)
• A list of groups of nodes along the explicit
route (generically called "source route")
• Thinking: source routing is better for calls
than hop-by-hop routing as it can take into
account loading conditions
• Constrained shortest path first (CSPF)
algorithm executed at the first node to
compute end-to-end route, which is
included in the ERO
35
Control-plane message transport:
inband or out-of-band
• Separation of control plane from data
plane in GMPLS networks - out-of-band
Internet
IP router
IP router
Control-plane messages
Ethernet control ports
GMPLS Network
Ethernet control ports
Circuit
established
SONET
or WDM switch
Data-plane link
SONET
or WDM switch
36
Interface ID field
• Control plane separation:
– Requires upstream switch to identify on which data-plane
interface the virtual circuit should be routed
– Interface ID field defined in the tag-length-value
format
– Embedded within the RSVP-HOP object
– Carried in PATH messages
37
Technologies
• GMPLS networks
– Data-(user-) plane protocols
• packet-switched: MPLS, VLAN Ethernet, Intserv IP
• circuit-switched: SONET/SDH, WDM, SDM
– Control-plane protocols:
• RSVP-TE: signaling protocol
 OSPF-TE: routing protocol
• LMP: link management protocol
• Internetworking
– GFP, VCAT, LCAS for SONET/SDH
– PWE3 for MPLS networks
– Digital wrapper for OTN
38
OSPF-TE: Open Shortest Path
First -Traffic Engineering
• To advertise loading conditions
• New parameters:
– Maximum bandwidth of a link
– Maximum reservable bandwidth: can be greater
than the maximum bandwidth to support
oversubscription
– Unreserved bandwidth
• RFC 3630 - for MPLS networks
• Only supports immediate-request
circuits/virtual circuits
– No time-dimension parameters for book-ahead
39
OSPF-TE extensions for GMPLS
• RFC 4202 and 4203
• Main new parameters
– Shared Risk Link Group
– Interface Switching Capability
Descriptor (ISCD)
• Allows multiple types of switching techniques
• Example for SONET: Minimum LSP
Bandwidth: OC1 on a SONET interface if the
switch demultiplexes down to OC1 level
40
Difference between labels in MPLS
and circuit-switched GMPLS
• In circuit-switched GMPLS networks, labels are
not carried in the data plane
– Labels in circuit-switched networks identify "position" of
data for the circuit - time or wavelength
• In circuit-switched GMPLS networks, cannot
assign labels without associated bandwidth
reservation
– In usage section, we will see the value of this feature in
MPLS networks
– See two applications: traffic engineering, VPLS
(addressing benefits)
41
Technologies
• GMPLS networks
– Data-(user-) plane protocols
• packet-switched: MPLS, VLAN Ethernet, Intserv IP
• circuit-switched: SONET/SDH, WDM, SDM
– Control-plane protocols:
• RSVP-TE: signaling protocol
• OSPF-TE: routing protocol
 LMP: link management protocol
• Internetworking
– GFP, VCAT, LCAS for SONET/SDH
– PWE3 for MPLS networks
– Digital wrapper for OTN
42
LMP procedures
• Control channel management
– Set up and maintain control channels between
adjacent nodes
• Link property correlation
– Aggregate multiple data links into a TE link
– Synchronize TE link properties at both ends
• Link connectivity verification (optional)
– Data plane discovery; If_Id exchange; physical
connectivity verification
• Fault management (optional)
– Fault notification and localization
43
Reference: IETF RFC 4204
Control-plane security
• Need authentication and integrity for
all control-plane exchanges
• Since RSVP, OSPF, LMP run over IP,
IPsec is a possible solution
44
Technologies
• GMPLS networks
– Data-(user-) plane protocols
• packet-switched: MPLS, VLAN Ethernet, Intserv IP
• circuit-switched: SONET/SDH, WDM, SDM
– Control-plane protocols:
• RSVP-TE
• OSPF-TE
• LMP
 Internetworking
– GFP, VCAT, LCAS for SONET/SDH
– PWE3 for MPLS networks
– Digital wrapper for OTN
45
Why internetworking?
• GMPLS networks do not exist as standalone
entities
• Instead they are part of the Internet:
– Obvious usage: to interconnect IP routers
– Newer uses:
• Commercial: interconnect Ethernet switches in
geographically distributed LANs via point-to-point
links or VPNs
• Research & Education networks: connect GbE and
10GbE cards on cluster computers and storage
devices to GMPLS networks
46
Obvious usage
• Router-to-router circuits and virtual
circuits
Internet
IP router
IP router
GMPLS Network
SONET
or WDM switch
SONET
or WDM switch
47
Router-to-router usage
• OSPF-enabled usage
– simply treat MPLS virtual circuit or
GMPLS circuit as a link between routers
– allow routing protocol to include these in
routing table computations
• Data-plane
– IP over MPLS
– IP over PPP over SONET
• Packet-over-SONET (PoS)
48
Newer uses
• New type of gateway functionality
– No IP layer involvement
– Instead Ethernet frames are mapped onto
MPLS virtual circuits or GMPLS circuits
• port mapped
• VLAN mapped
• Cisco and Juniper routers support
Ethernet over MPLS
• Sycamore and Ciena SONET switches
support Ethernet over GMPLS
49
Ethernet port mapped
over MPLS
SDM-to-MPLS gateway
IP router/MPLS switch
I
Internet
Pseudowire
SDM-to-MPLS gateway
IP router/MPLS switch
II
MPLS LSP (virtual circuit)
Ethernet switch
Enterprise 1
•
•
•
•
Mux scheme on pseudowire: Ethernet
Ethernet switch
Enterprise 2
Gateway: interfaces have different MUX schemes
unlike switch, which has same MUX scheme on all links
Send all Ethernet frames received on ports I and II on to the MPLS LSP
MPLS LSP: Pseudo-wire
Enterprise can allocate IP addresses from one subnet: Virtual Private LAN
Service (VPLS)
Explains one use for MPLS virtual circuits with no bandwith allocation
SDM: Space Division Multiplexing
50
Ethernet VLAN mapped
over MPLS
VLAN-to-MPLS gateway
IP router/MPLS switch
Internet
VLAN-to-MPLS gateway
IP router/MPLS switch
II
I
MPLS LSP
Ethernet switch
Enterprise 1
Ethernet switch
Enterprise 2
• Extract frames carrying a specific VLAN ID tag on Ethernet
ports I and II and map only these frames on to the MPLS LSP
51
Ethernet port or VLAN mapped
over GMPLS circuits
SDM-to-SONET/WDM gateway
SONET or WDM switch
SDM-to-SONET/WDM gateway
SONET or WDM switch
II
I
Ethernet switch
Enterprise 1
•
•
SONET/SDH/WDM
circuit
Ethernet switch
Enterprise 2
Send all frames or frames matching a given VLAN ID tag from
Ethernet ports I and II on to the SONET/SDH/WDM circuit
SONET/SDH/WDM switches now have Fast Ethernet/GbE/10GbE
interfaces in addition to SONET/SDM or WDM interfaces
52
Commercial services
• EPL: Ethernet private line: map an
Ethernet port to a SONET/SDH circuit
• Fractional-EPL: Map a GbE port to a lowerrate SONET circuit
– Pause frames sent from switch to client node if
buffer fills up
• V-EPL: Lower-rate VLAN mapped to an
equivalent-rate SONET circuit
• MetroEthernet Forum: E-Line and E-LAN
53
page 110 of GFP section reference: SONET focused
Technology
• So what technologies are required for
this type of internetworking:
– mapping Ethernet frames on to
MPLS/GMPLS virtual circuit/circuit
mapping?
54
Technologies
• GMPLS networks
– Data-(user-) plane protocols
• packet-switched: MPLS, VLAN Ethernet, Intserv IP
• circuit-switched: SONET/SDH, WDM, SDM
– Control-plane protocols:
• RSVP-TE
• OSPF-TE
• LMP
• Internetworking
 GFP, VCAT, LCAS for SONET/SDH
– PWE3 for MPLS networks
– Digital wrapper for OTN
55
Why do we need Generic
Framing Procedure (GFP)?
• The framing techniques used in other data-link layer
protocols have problems
• For example, IP packets are carried over SONET using
PPP/HDLC frames (called PoS)
– HDLC inserts idle frames because SONET is synchronous it
needs a constant flow of frames to avoid losing synchronization
• But, there is a problem:
– HDLC uses flags for frame delineation. The issue with this
framing technique is that if the flag pattern occurs in the
payload, an escape byte has to be inserted
– This causes an increase in the required bandwidth
– The amount of increase is payload-dependent
56
page 98 of reference
Other framing techniques
• HEC - Header Error Control
– this is the CRC framing technique used in ATM
– "A header CRC hunting mechanism is employed by the receiver
to extract the ATM cells from the bit/byte synchronous
stream. The HEC location is fixed and ATM cell length is fixed.
Starting from the assumed cell boundary, the ATM receiver
compares its computed HEC value for the assumed ATM cell
header against the HEC value indicated by the assumed HEC
field. Cell stream delineation is declared after positive
validations of the incoming HEC fields of a few consecutive
ATM cells."
• ATM cells are fixed in length, but Ethernet frames are
variable-length
• Therefore, we need a length field in order to implement this
HEC-based frame delineation mechanism
57
pages 96-97 of reference
Main features of the
GFP protocol
• Common aspects (applicable to all client signals):
– HEC + Length based delineation
• Core header has payload length and HEC
– Error control: error detection
• Payload type HEC, payload Frame Check Sequence (CRC-32)
– Multiplexing: linear and ring extension headers
– Idle frames are sent to maintain synchronization as in
HDLC
– Scrambling as in ATM:
• core header + payload scrambling
– Client management - client fail signal
• Client-dependent aspects:
– Client-specific encapsulation techniques
page 68 of reference
58
Virtual Concatenation (VCAT)
for increased efficiency
Data signal
SONET/SDH payload mapping
and bandwidth efficiency
SONET/SDH with VCAT
payload mapping and bandwidth
efficiency
Ethernet
(10 Mb/s)
STS-1/VC-3 – 21%
VT1.5-7v/VC-11-7v – 89%
Fast Ethernet
(100 Mb/s)
STS-3c/VC-4 – 67%
VT1.5-64v/VC-11-64v – 98%
Gigabit Ethernet
(1000 Mb/s)
STS-48c/VC-4-16c – 42%
STS-3c-7v/VC-4-7v –95%
STS-1-21v/VC-3-21v –98%
59
Page 75 of reference
Inverse multiplexing in VCAT
Implementation of VCAT is only required at select nodes (i.e.,
the edge nodes); not all multiplexers need to support VCAT
60
Page 82 of reference
Link Capacity Adjustment Scheme
(LCAS)
• LCAS is a mechanism to allow for automatic
bandwidth tuning of a virtually
concatenated signal
– The VCAT group of circuits should already be
established using a
• centralized NMS/EMS based procedure, or
• by a distributed RSVP-TE based procedure
• Note that bandwidth cannot be increased
beyond the aggregate value of the VCAT
signal without a GMPLS RSVP or NMS/EMS
procedure of circuit setup
61
Link Capacity Adjustment Scheme
(LCAS)
• LCAS is a synchronization procedure between the two ends
of a VCAT signal
– Unlike GMPLS RSVP, it is NOT a bandwidth reservation and
circuit setup or release procedure
• LCAS procedures (triggered by GMPLS or NMS/EMS):
– add or remove a member of a VCAT group
– renumber the members in a VCAT group
• Messages are exchanged between the originating and
terminating SONET/SDH nodes to execute these LCAS
procedures
– Add member (ChID, GID)
– Remove member (ChID, GID)
– Member status
• Messages are sent in the H4 byte for high-order VCAT
62
Technologies
• GMPLS networks
– Data-(user-) plane protocols
• packet-switched: MPLS, VLAN Ethernet, Intserv IP
• circuit-switched: SONET/SDH, WDM, SDM
– Control-plane protocols:
• RSVP-TE
• OSPF-TE
• LMP
• Internetworking
– GFP, VCAT, LCAS for SONET/SDH
 PWE3 for MPLS networks
– Digital wrapper for OTN
63
Pseudo Wire Emulation
• Pseudo Wire Emulation Edge-to-Edge (PWE3) is a
mechanism for emulating certain services across a
packet-switched network:
– Services: Frame-relay, ATM, Ethernet, TDM services,
such as SONET/SDH
– Packet-switched network:
• IP
• MPLS
– Common usage: Ethernet service over MPLS
• Port-mapped to MPLS LSP
• VLAN mapped to MPLS LSP
– IETF RFC 3985
Digital wrapper
• ITU-T G. 709 provides a method to
carry Ethernet frames, ATM cells, IP
datagrams directly on a WDM
lightpath
65
Outline
• Principles
– Different types of connection-oriented
networks
• Technologies
– Single network
– Internetworking
Usage
– Commercial networks
– Research & Education Networks (REN)
66
Commercial uses
• Semi-permanent MPLS virtual circuits
– Traffic engineering
– Voice over IP
• QoS concerns: telephony has a 150ms oneway delay requirement (with echo cancellers)
– Business or service provider interconnect
• interconnecting geographically distributed
campuses of an enterprise
• interconnecting wide-area routers of an ISP
service provider
67
Traffic engineering (TE)
• Since BGP and OSPF routing protocols mainly
spread reachability information, routing tables are
such that some links become heavily congested
while others are lightly loaded
• MPLS virtual circuits are used to alleviate this
problem
– e.g., NY to SF traffic could be directed to take an MPLS
virtual circuit on a lightly loaded route avoiding all paths
on which more local traffic may compete
• This is an application of MPLS VCs without
bandwidth allocation
68
Goals of Traffic Engineering (TE)
• Monitor network resources and control traffic to
maximize performance objectives
– Goal of TE is to achieve efficient network operation with
optimized resource utilization in an Autonomous System
• Goals of TE can be:
– Traffic oriented
• Enhance the QoS of traffic streams
• Minimization of loss and delay
• Maximization of throughput
– Resource oriented
• Load balancing
• Minimize maximum congestion or minimize maximum
resource utilization
• Output – decreased packet loss and delay, increased
throughput
69
Business or service provider
interconnect
• Multiple options:
– TDM circuits (traditional private line, T1, T3,
OC3, OC12, etc.)
– Ethernet private line
• point-to-point (Ethernet over MPLS/SONET/WDM)
• VPNs (called Virtual private LAN service)
– MPLS VPNs
– WDM lightpaths
– Dark fiber
70
Dynamic circuits/virtual circuit
(GMPLS control-plane)
• Commercial:
– fast restoration
• circuit/VC setup delay significant
– rapid provisioning
• Verizon: Bandwidth on Demand (Just-in-Time
Provisioning)
• AT&T: Shared mesh networks
– Customer Applications for dynamic network configuration
» Key industries: Financial, Media & Entertainment
» Corporate Utility Backbone Networks (e.g. reconfigure
for disaster recovery)
» Distribution of real-time content (e.g., Video)
• Level3: Vyvx service
71
Research & Education
(G)MPLS networks
•
•
•
•
•
Internet2’s Dynamic Circuit network
NSF-funded DRAGON
DOE's ESnet - Science Data Network
DOE's Ultra Science Network (USN)
NSF-funded CHEETAH
72
Internet2 DWDM network
Infinera
DWDM system
http://events.internet2.edu/speakers/speakers.php?go=people&id=178
Rick Summerhill talk (10/11/2007)
Internet2
Dynamic Circuit (DC) network
Ciena CD-CI
Eth-SONET
switch
http://events.internet2.edu/speakers/speakers.php?go=people&id=178
Rick Summerhill talk (10/11/2007)
Internet2 IP-routed network
IP-router-to-router links on one wavelength
SONET switch-to-switch links on another wavelength
Ciena CD-CI
Eth-SONET
switch
Juniper
T640 IP router
http://events.internet2.edu/speakers/speakers.php?go=people&id=178
Rick Summerhill talk (10/11/2007)
Equipment at each PoP
http://events.internet2.edu/speakers/speakers.php?go=people&id=178
Rick Summerhill talk (10/11/2007)
Control-plane software
(for DC network)
• OSCARS implemented in InterDomain
Controller (IDC) - one per domain
– Abstracted topology exchange
– Interdomain scheduling
– Interdomain signaling (for provisioning)
• DRAGON (intradomain control-plane)
– Used in Internet2’s DC network
– Intradomain routing, path computation,
signaling (for provisioning)
77
OSCARS
• On-demand Secure Circuits and Advance Reservation
System (OSCARS)
• DOE Office of Science and ESnet project
• Co-development with Internet2
• Web Service based provisioning infrastructure, which
includes scheduling, AAA architecture using X.509
certificates
– Extended to include the DICE IDCP
– Reservations held in SQL database
• Recall no support for book-ahead in GMPLS control protocols
• http://www.es.net/oscars/index.html
http://www.csm.ornl.gov/workshops/NetworkingResearchChallenges/agenda.html
Talk by Tom Lehman, Sep. 28, 2008
78
DRAGON
•
Washington DC metro-area network:
– Adva (old Movaz) WDM switches and Ethernet switches (G.709)
•
Control-plane software:
– Network Aware Resource Broker – NARB
• Intradomain listener, Path Computation
– Virtual Label Swapping Router – VLSR
• Implements OSPF-TE, RSVP-TE
• Run on control PCs external to switches (since not all switches implement
these GMPLS control-plane protocols)
• Communicates with switches via SNMP, TL1, CLI to configure circuits.
– Client System Agent – CSA
• End system software for signaling into network (UNI or peer mode)
– Application Specific Topology Builder – ASTB
• User Interface and processing which build topologies on behalf of users
• Topologies are a user specific configuration of multiple LSPs
http://dragon.east.isi.edu
79
Open Source
DCN Software Suite
• OSCARS (IDC)
– Open source project maintained by ESNet and Internet2
– Uses WDSL, XML, SQL database to store reservations
– Reservations accepted with 1 minute granularity
• DRAGON (DC)
– NSF-funded Open source project maintained by USC ISI
EASTand MAX
• Version 0.4 of DCNSS current deployed release
– https://wiki.internet2.edu/confluence/display/DCNSS
• DCN workshops offered for training:
– http://www.internet2.edu/workshops/dcn/index.html
http://www.csm.ornl.gov/workshops/NetworkingResearchChallenges/agenda.html
Talk by Tom Lehman, Sep. 28, 2008
80
DICE IDCP
•
•
•
•
Dante, Internet2, CANARIE, ESNet
http://www.controlplane.net
IDCP: InterDomain Controller Protocol
wsdl - web service definition of message
types and formats
• xsd – definition of schemas used for
network topology descriptions and path
definitions
http://www.csm.ornl.gov/workshops/NetworkingResearchChallenges/agenda.html
Talk by Tom Lehman, Sep. 28, 2008
81
InterDomain Controller (IDC)
Protocol (IDCP)
•
The following organizations have implemented/deployed systems which are
compatible with this IDCP
–
–
–
–
–
–
–
–
–
–
–
–
•
Internet2 Dynamic Circuit Network (DCN)
ESNet Science Data Network (SDN)
GÉANT2 AutoBahn System
Nortel (via a wrapper on top of their commercial DRAC System)
Surfnet (via use of above Nortel solution)
LHCNet (use of I2 DCN Software Suite)
Nysernet (use of I2 DCN Software Suite)
LEARN (use of I2 DCN Software Suite)
LONI (use of I2 DCN Software Suite)
Northrop Grumman (use of I2 DCN Software Suite)
University of Amsterdam (use of I2 DCN Software Suite)
DRAGON Network
The following "higher level service applications" have adapted their existing
systems to communicate via the user request side of the IDCP:
–
–
–
LambdaStation (FermiLab) – CMS project on Large Hadron Collider
TeraPaths (Brookhaven) - ATLAS project on Large Hadron Collider
Phoebus
http://www.csm.ornl.gov/workshops/NetworkingResearchChallenges/agenda.html
Talk by Tom Lehman, Sep. 28, 2008
82
Heterogeneous Network Technologies
Complex End to End Paths
Example: DRAGON
AS 1
Example: Internet2 DC
Example: ESNet SDN
AS 2
IP Control Plane
IP Control Plane
AS 3
IP Control Plane
VLSR
VLSR
Ethernet over WDM
End
System
Ethernet Segment
VLSR Established VLAN
Ethernet over
SONET
Ethernet
Lambda Switch
SONET Switch
Router MPLS LSP
End
System
Ethernet Segment
VLSR Established VLAN
Router
http://events.internet2.edu/speakers/speakers.php?go=people&id=178
Rick Summerhill talk (10/11/2007)
IDCP operation
Route selection,
admission control
centralized per
domain at IDC
•
•
•
Advance reservation request and circuit provisioning at scheduled time:
•
End user signals IDC with a reservation request
•
Authenticate requester and check authorization
•
Request reservation (create time, bandwidth, VLAN tag)
•
Signaling: creation of circuit (automatic or in response to message to IDC)
Topology exchange: interdomain (abstracted topology information)
Monitoring
84
http://hpn.east.isi.edu/dice-idcp/dice-idcp-v1.0/idc-protocol-specification-may302008.doc
Intra-domain operations
• Using DRAGON in Internet2 DCN
– NARB does intra-domain path computation after
collecting routing information by listening to OSPF-TE
exchanges between VLSRs
– These intradomain paths are provided to IDC for use
during resource scheduling (upto 3 path options are
considered)
– 5 VLSRs serve 22 CD-CIs: “subnets of CD-CIs”
– In Signaling phase, VLSR sends TL1 command to edge CDCI, which initiates proprietary hop-by-hop signaling to
configure circuit through subnet
85
GOLE: GLIF open lightpath exchange
86
DOE networks
• ESnet and Science Data Network (SDN)
– OSCARS: an advance-reservation system
– Science Data Network: MPLS network
• UltraScience Network
–
–
–
–
Research network for DoE labs
GbE and SONET (Ciena CD-CI)
Centralized scheduler for advance-reservation calls
5-PoP network: ORNL, Atlanta, Chicago, Seattle,
Sunnyvale
– Connections to Fermi Lab, PNNL, SLAC, CalTech
• Lambdastation: CMS project
– Between Fermi Lab and Univ. of Nebraska
87
NSF-funded CHEETAH network
GbEthernet and SONET
UVa
TN PoP
SN16000
CUNY
GbE
GbE
OC192 Control GbE/
10GbE
card
card
card
NCSU
End hosts
GbEs
GbE
OC-192
NC PoP
GA PoP
SN16000
End
GbE GbE/
Control OC192
10GbE card
hosts
cards
card
ORNL
GbE
SN16000
OC192 Control GbE/ GbE
10GbE
card
card
End
card
OC-192
hosts
GbE
88
Sycamore SN16000
SONET switch with GbE/10GbE interfaces
GaTech
Networking software
• Sycamore switch comes with built-in GMPLS
control-plane protocols:
– RSVP-TE and OSPF-TE
• We developed CHEETAH software for Linux
end hosts:
– circuit-requestor
• allows users and applications to issue RSVP-TE
call setup and release messages asking for
dedicated circuits to remote end hosts
– CircuitTCP (CTCP) code
http://www.ece.virginia.edu/cheetah/
89
CHEETAH network usage
End Host
CHEETAH
software
IP-routed
network
DNS client
RSVP-TE module
Application
End Host
CHEETAH
software
DNS client
SONET circuitswitched network
RSVP-TE module
TCP/IP
Application
TCP/IP
NIC 1
CTCP/IP
NIC 2
Circuit
Gateway
Circuit
Gateway
NIC 1
NIC 2
CTCP/IP
• Bandwidth-sharing mode:
•
•
Immediate-request mode
Heterogeneous rate allocation under high loads:
• higher BW for large files than for small files
• Applications:
•
Common file transfers (web, P2P, CDN, storage)
•
•
attempts circuits for large files (if blocked, use IP-routed path)
use IP-routed path for small files
90
End-to-end call setup delay
measurements
•
Delays incurred in setting up a circuit between host zelda1 (in Atlanta, GA) and
host wuneng (in Raleigh, NC) across the CHEETAH network
Circuit type
End-to-end
circuit setup
delay (s)
Processing delay for
Path message at
the NC SN16000 (s)
Processing delay for
Resv message at
the NC SN16000 (s)
OC-1
0.166103
0.091119
0.008689
OC-3
0.165450
0.090852
0.008650
1Gb/s EoS
1.645673
1.566932
0.008697
Round-trip signaling message propagation plus emission delay between GA SN16000 and NC SN16000:
0.025s
•
Observations:
–
–
–
Setup delays for SONET circuits (OC1, OC3) are small (166ms)
Setup delays for Ethernet-over-SONET (EoS) hybrid circuits are much higher (1.6s)
(no standard; proprietary implementation)
Signaling message processing delays dominate end-to-end circuit setup delays
91
Spectrum of services
New services
Leased line
Verizon BoD
Book-ahead mode
Call duration specified
Current solution:
• centralized per-domain path
computation/admission control
Low call handling volume
OSCARS/DRAGON
eScience
10G POTS
IP
Plain Old Telephone Service (64kbps)
Immediate-Request (IR) mode
Unspecified call duration
Low call setup overhead
( holding times can be shorter)
Distributed path computation/admission
control
High call handling volume
CHEETAH
92
Summary
• Principles
– Different types of connection-oriented
networks
• Technologies
– Single network: MPLS, SONET, OTN
– Internetworking: PWE3, GFP, G.709
• Usage
– Commercial networks
– Research & Education Networks (REN)
93
References on bandwidth sharing modes
•
•
•
•
•
•
X. Fang and M. Veeraraghavan, “On using a hybrid architecture for
file transfers,” acceptedto IEEE Transactions on Parallel and
Distributed Systems, 2009.
X. Zhu and M. Veeraraghavan, "Analysis and Design of Book-ahead
Bandwidth-Sharing Mechanisms," IEEE Transactions on
Communications, Dec. 08.
X. Fang and M. Veeraraghavan, On using circuit-switched networks
for file transfers,” in IEEE Globecom, New Orleans, LA, Nov. 2008.
X. Zhu, M. E. McGinley, T. Li, and M. Veeraraghavan, "An Analytical
Model for a Book-ahead Bandwidth Scheduler," in IEEE Globecom
Washington, DC, Nov. 2007.
X. Zhu, X. Zheng, and M. Veeraraghavan, "Experiences in
implementing an experimental wide-area GMPLS network," IEEE
Journal on Selected Areas in Communications (JSAC), Apr. 2007.
M. Veeraraghavan, X. Fang, and X. Zheng, “On the suitability of
applications for GMPLS networks,” in IEEE Globecom, San
Francisco, CA, Nov. 2006.
94
References for OTN
• ITU-T G. 872 and G.709/Y.1331 Specifications
• T. Walker, “Optical Transport Network (OTN) Tutorial”,
Available online: http://www.itu.int/ITUT/studygroups/com15/otn/OTNtutorial.pdf
• Agilent, “An overview of ITU-T G.709,” Application Note
1379
• P. Bonenfant and A. Rodriguez-Moral, "Optical Data
Networking," IEEE Communications Magazine, Mar. 2000, pp.
63-70.
• E. L. Varma, S. Sankaranarayanan, G. Newsome, Z.-W. Lin,
and H. Esptein, “Architecting the Services Optical
Network,” IEEE Communications Magazine, Sept. 2001, pp.
80-87.
95
References for OSPF-TE
•
•
•
•
•
•
•
•
RFC 2702 - Requirements for Traffic Engineering Over MPLS:
http://www.faqs.org/rfcs/rfc2702.html
RFC 3630 - Traffic Engineering (TE) Extensions to OSPF Version 2:
http://www.faqs.org/rfcs/rfc3630.html
RFC 4203 - OSPF Extensions in Support of Generalized Multi-Protocol Label
Switching (GMPLS) : http://www.ietf.org/rfc/rfc4203.txt
RFC 2328 - OSPF Version 2 : http://www.ietf.org/rfc/rfc2328.txt
OSPFv2 Routing Protocols Extensions for ASON Routing:
http://www.ietf.org/internet-drafts/draft-ietf-ccamp-gmpls-ason-routingospf-02.txt
RFC 4202 - Routing Extensions in Support of Generalized Multi-Protocol
Label Switching (GMPLS): http://www.ietf.org/rfc/rfc4202.txt
RFC 3471- Generalized Multi-Protocol Label Switching (GMPLS) Signaling
Functional Description: http://www.faqs.org/rfcs/rfc3471.html
Dimitri Papadimitriou, IETFInternet Draft, "OSPFv2 Routing Protocols
Extensions for ASON Routing," draft-ietf-ccamp-gmpls-ason-routing-ospf02.txt, October 2006.
96
Reference for
GFP/VCAT/LCAS
• IEEE Communications Magazine, May
2002, Special issue on "Generic
Framing Procedure (GFP) and Data
over SONET/SDH and OTN," Guest
Editors, Tim Armstrong and Steven S.
Gorshe
• 6 excellent papers
97
References for REN projects
• IEEE Communication Magazine special
issue, March 2006
– DRAGON, UltraScience Net, CHEETAH,
several other projects
98