Transcript Chapter 4 Lecture Presentation

Application 2: Automatic private
line bandwidth modification
Malathi Veeraraghavan
University of Virginia
[email protected]
Nov. 20, 2007

Outline




Private line view vs. IP view
"Vertical" vs. "horizontal" triggers of SPC/SC
setup/release
CHEETAH testbed and software
Prototype automatic PL bandwidth modification
application
Presentation for Sycamore Networks
1
Control plane

Key differentiator for SN16000


What type of network service is enabled
by control-plane software?


Control plane
Dynamic circuit service (DCS)
What is missing:

Applications that will trigger dynamic circuit
service
2
Type of services offered today
Private line (PL)

Private line (PL) or leased line services



IP
Business interconnect
Internet access
IP service
3
Introduction of DCS
Private line

Dynamic circuit services (DCS)
IP
How can DCS be introduced within the
existing context of PL and IP services?


PL bandwidth modification
Dynamic CDN

Application 1 discussed in previous set of slides
4
PL bandwidth modification

Carrier approach (using Verizon example)


Provide business customer web portal access to
manually request increase or decrease of PL
bandwidth
Basis for this approach:

PL bandwidth modification is only required
when aggregate traffic needs change
5
Current ITU-T approach: "vertical"
Draft new Recommendation G.7718/Y.1709 (for consent)
NMS
SPC
setup
EMS.1
SPC
setup
EMS.2
EMS.3
trad.
conn.
setup
non-ASON
ASON
control
Control Domain
nonASON
Traditional
control by
NMS/EMS
Control Domain
nonASON
ASON
control
non-ASON
Control Domain
Figure I 5/G.7718/Y.1709 Hybrid intra-carrier network for SPCs (simple case)


NMS triggers SPC setup, modify, release
Verizon's web portal likely communicates
with NMS
6
Key point

Need for increased speed of PL:



Single file transfer
Instead of only when aggregate traffic increases
Our recommendation:

"Horizontal" approach


trigger SPC setup from end host file-transfer
applications
Provide software in servers located at business
to allow an enterprise user to request
additional bandwidth on a PL for a single highspeed file transfer
7
Horizontal approach: SPC/SC setup trigger from
end-host application, e.g. storage
Enterprise
Storage
server
1GigE
1GigE
IP router
Private line (PL)
carrier
metro ring
or metro mesh
network
Enterprise
1GigE
Business interconnect
PL (300 Mbps)



Host
1GigE
IP router
Private line leased between business locations:
OC3c-2v (300Mbps)
Router interface cards: 1GiGE
Rate limiting enforced on SN16000 GiGE ports
8
Horizontal thinking: SPC setup trigger from user
application, e.g. storage
Enterprise
Enterprise
Storage
server
1GigE
Host
DCS
server
4
1GigE
IP router
Private line (PL)
carrier
metro ring
or metro mesh
network
3
DCS
server
2


Storage
client
DCS
1client
1GigE
Business interconnect
PL (300 Mbps)

1
Dynamically increase PL rate to 1Gbps
Decreases file transfer delay
Assumes PL is the bottleneck link
1GigE
IP router
9
Steps in previous slide





1: When storage client starts a backup, the DCS client
sends a message to DCS server
2: DCS server communicates via EMS or directly to
SN16000 to set up additional OC3c's, increase rate limit
on GiGE port, and thus increase end-to-end bottleneck link
rate to 1Gb/s
3: For scalability, deploy one DCS server per SN16000;
signal egress SN16000 about increase
4: sets rate limit on GigE port
5: (not shown in figure) When files are transferred,
storage client through the signaling client can have the
DCS server initiate release of additional OC3c's and
decrease rate limit to 300Mbps
10
UNI-C support in routers



Currently only high-end routers such as
Cisco's CRS-1 and 12008XR router
supports UNI-C
Business routers are not likely to be these
high-end routers
Alternative solution feasible if UNI-C is to
used to invoke additional OC3c circuit
setup

Have DCS server deployed per IP router
11
G.7718 states

"The CP-MP interface shall support ...







The ability to invoke the setup of a SPC
The ability to invoke the release of a SPC
The ability to invoke the modify operation of a SPC
...
Notifications of the setup, release and modifications of
SCs"
Private line type view
Notifying MP of SPC/SCs will be too expensive if
SPC/SCs are short-held
12
PL view vs. IP view

The ITU-T approach: "PL view"



Views the provisioning of SPCs and SCs as
comparable to "private line"
Durations: Long-held
"IP view"


While an IP router keeps count of the number
of packets in and out of its interfaces, it does
not "notify" the management plane about every
packet that arrives on its interfaces
Apply this view to SPC or SC setups/releases
invoked by "horizontal" host applications
13
Two "new" concepts

Increase speed for single file transfers


Rather than only when aggregate demand
increases
Invoke SPC/SC setup/release from end
host applications rather than from NMS
14
File transfer delay
r1




r3
r4
r5
File transfer delay is determined by


r2
bottleneck link rate, r = min(r1, r2, r3, r4, r5)
packet loss rate on end-to-end path, Ploss
round-trip time (RTT)
On lightly loaded paths, RTT and Ploss do not
matter for large files
Only bottleneck link rate, r, matters
15
Throughput - approximate
formula
MSS 1
reffective  min(r ,

)
RTT
p


Throughput is effective rate, reffective
Parameters





r: Bottleneck link rate
RTT: Round-Trip Time
MSS: Maximum Segment Size
p: Packet loss on the path
The macroscopic behavior of the TCP congestion
avoidance algorithm by Mathis, Semke, Mahdavi & Ott in
Computer Communication Review, 27(3), July 1997
16
TCP/IP file-transfer delays

In heavily loaded paths, e.g., if






Ploss = 1%
RTT = 50ms
effective transfer rate  1.8Mbps
if r is more than this value, it does not determine
effective rate. Ploss and RTT are main factors.
if increasing r causes Ploss to decrease, effective
rate can be improved.
Metro area, e.g.


RTT = 1ms, Ploss = 1%
effective transfer rate  75Mbps
17
File-transfer delay
(approximation)
D

S
reffective
For large files:



File-transfer delay: D (sec)
File size: S (bits)
Throughput: reffective (b/s)
18
Outline check

Outline




Private line view vs. IP view
"Vertical" vs. "horizontal" triggers of
SPC/SC setup/release
CHEETAH testbed and software
Prototype automatic PL bandwidth
modification application
19
CHEETAH concept
CHEETAH implementation
Internet
End Host
Application
RSVP-TE client
TCP/IP
C-TCP/IP
End Host
NIC 1
NIC 2
Application
RSVP-TE client
SONET
circuitswitched
network
SN16000
NIC 1
SN16000
NIC 2
TCP/IP
C-TCP/IP
Circuit-TCP: TCP minus congestion control;
use if circuit is host-to-host.
Use high-speed circuit for file transfer applications
Circuits: GigE VLAN mapped to OC3cNv circuit mapped to GigE VLAN
NIC1 and NIC2: GigE network interface cards
SN16000 links to Internet: Ethernet management ports
20
IPsec tunnels used on Internet control-plane
Signaling and routing




RSVP-TE client developed for end hosts (Linux
PCs) sends RSVP-TE messages to Sycamore
SN16000.
Built-in controller of SN16000 used for dynamic
call setup and release
OSPF-TE used between SN16000 switches
Solution works with 7.6.2.1 release of SN16000
software:


GbE mapped to OC3-7v
Extending for VLANs and sub-Gbps rates
21
CHEETAH end-host software

RSVP-TE client software architecture
End Host
circuitrequestor
bwlib
Sig_proc
Connection Admission Control:
check if bandwidth is available
on the UNI from the host to the
switch (multiple VLANs)
CAC
Data-plane
Configuration
Parsing/
Construction
read
RSVPD
RSVP-TE
messages
Configuration file
Configure IP routing and ARP table
since remote host is reached directly on
the newly setup circuit
22
CHEETAH testbed
GbE
Raleigh,
NC
ORNL, TN
SN16000
SN16000
Zelda4/5
OC192
OC192
3xGbE
Zelda1/2/3
Wukong/
Wuneng
SN16000
Atlanta
• Long-distance OC192s purchased from NLR and ORNL
• Collocation services purchased from MCNC in NC, SLR in Atlanta
• Zeldas and wukong/wuneng: Linux Dell PCs
23
Outline check

Outline




Private line view vs. IP view
"Vertical" vs. "horizontal" triggers of
SPC/SC setup/release
CHEETAH testbed and software
Prototype "automatic PL bandwidth
modification" application for storage
24
New implementation required



DCS server
DCS client
Shell script to wrap storage (or other suitable
business file-transfer application) with DCS
client


Business end user "unaware" that application is
requesting bandwidth increase prior to file transfer
EMS software to obtain RSVP-TE logs on dynamic
circuit setup/release for usage-based billing
support
25
Summary



Opportunity to leverage SN16000's strength in control
plane implementation
While control-plane allows carriers to offer Dynamic
Circuit Service (DCS), without applications, the service is
not likely to be used by business customers
Applications identified for DCS:




Dynamic CDN
Automatic PL bandwidth modification
CHEETAH SN16000 based testbed available for testing
applications
Looking for support:


Student HR support to implement applications for dynamic
circuit services
Cheetah testbed annual maintenance charges
26