download
Post on 25-Jun-2015
242 Views
Preview:
TRANSCRIPT
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 1
IPTV / IPMulticast End-to-End
Greg Shepherd (shep@cisco.com)
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 2
Agenda
IPTV Deployments
Impact of Packet Loss on MPEG2 Frames
Network Impairment Contributors
CRS IPMulticast Test Data
Summary
Future Challenges
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 3
IPTV Deployments today
Two schools of thought in deployments today:1) I think I need 50ms cvg
2) IPMulticast is fast enough
IPMulticast is UDPThe only acceptable loss is 0ms
How much is “reasonable”?
50ms “requirement” is not a video requirementLegacy telco voice requirement
Efforts for 50ms only cover a limited portion network events
Where to put the effort?Make IPMulticast better?
Improve the transport?
Add layers of network complexity to improve core convergence?
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 4
Agenda
IPTV Deployments
Impact of Packet Loss on MPEG2 Frames
Network Impairment Contributors
CRS IPMulticast Convergence Test Data
Summary
Future Challenges
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 5
0% Packet Loss
Impact of Packet Loss on MPEG Stream
0.5 % Packet Loss
5 % Packet Loss
Video is very susceptible to IP Impairments
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 6
Impact of Packet Loss on MPEG Stream
Compressed Digitized Video is sent as I, B, P Frames I-frames: contain full picture information
Transmit I frames approximately every 15 frames (GOP interval)
P-frames: predicted from past I or P frames B-frames: use past and future I or P frames
I B B P B B P B B P B BI B B P B B P B B P B B
I-frame loss “corrupts” P/B frames for the entire GOP
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 7
Impact of Packet Loss on MPEG Stream
Example Assumptions:MPEG2 stream CBR = 4.8828Mbps
MPEG2 IP stream pps = 427.35pps
L3 pkt_size = 1487Bytes (encap IP + UDP + RTP)
GOP-size-in-msec 480
GOP-size-in-pkts 205
Network events create correlated packet loss, not random single packet loss.
What’s the relationship between network CVG time and I-frame loss?
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 8
MPEG Frame Impact from Packet Loss
0%
20%
40%
60%
80%
100%
120%
0 50 100 150 200 250 300 350 400 450
Impairment (ms)
% Chance of Lost Frame
I-Frame
P-Frame
B-Frame
32%
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 9
MPEG Frame Impact from Packet Loss
P/B frame loss is less noticeableError concealment techniques in the receiver can mask some
I-Frames loss is more problematicI-frame loss can result in an entire GOP loss
A single packet lost from an I-frame corrupts the entire I-frame
I-frame (GOP) loss can result in blank screen for 1-2 secs
50ms is a phantom goal32% chance of I-frame loss
..another way..
32% of your streams will have 1-2 sec blank screen outage
Why then is this a goal for some?
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 10
Agenda
IPTV Deployments
Impact of Packet Loss on MPEG2 Frames
Network Impairment Contributors
CRS IPMulticast Convergence Test Data
Summary
Future Challenges
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 11
What are the Impairment Contributors?
Link Failures
Node Failures
Random Uncorrected Bit Errors
Congestion
How do we measure these?
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 12
What are the Impairment Contributors?
1st: Need Quantify ImpairmentsNeed some “standard”
Relevant to viewers’ experience
# Impairments per 2 hoursRepresentative of a typical movie duration
Allow for comparing contributions over a standard window of time
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 13
What are the Impairment Contributors?
Some Assumptions / Some Industry Standard Data / Some Customer Experience Data
Total Value Across a Typical Provider Network
Trunk Failures - .0010 Imp/2hr
HW Card Failures - .0003 Imp/2hr
SW Failures - .0012 Imp/2hr
NSF/SSO reduces the realized amount of this contribution
SW Upgrades - .0037 Imp/2hr
Modular code (IOS-XR) reduces the realized amount of this contribution
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 14
What are the Impairment Contributors?
Uncorrected Bit Errors - 11.4629 Imp/2hrs"Video over IP" by WesSimpson (page 238) - 10-10 per trunk
Trunk Failures: .0010HW Failures: .0003SW Failures: .0012Maintenance: .0037Total: .0062 Imp/2hrs
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 15
Network Impairment Contributors
All HW/SW/Link failures combined do not compare to uncorrected bit errors
Last-mile networks often most significant contributors
SW failures/Maintenance each contribute much more than link failures
Stable, modular software with NSF/SSO can reduce this contribution even further
Fast convergence in the core is a worthy goalImproves core-contributed artifacts
Need to consider the balance of a solid platform vs. layered complexity
Solid performing platform is more important than complex protocol solutions
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 16
Agenda
IPTV Deployments
Impact of Packet Loss on MPEG2 Frames
Network Impairment Contributors
CRS IPMulticast Convergence Test Data
Summary
Future Challenges
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 17
Internal CRS Multicast Convergence Test
Typical customer topologies
Most tree repairs are single-hop repairs
Typical customer network configurations
2500 IGP routes
250k BGP routes
Tests of 400 - 4000 (S,G) SSM entries
ISIS Prefix Prioritization
Loopbacks
Multicast source prefixes
Not yet in OSPF
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 18
Summary across all available CRS1 data
And most important… CRS1 SSM Convergence is rather quick!
SSM Convergence as a function of the number of IPTV channels
0 100 200 300 400 500 600 700 800 900 1000
1A ACL 400 isis2500bgp250k
1A ACL 800 isis2500bgp250k
1A ACL 4000 isis2500bgp250k
ms
max of max
median of median
4000 IPTV channels
800 IPTV channels
400 IPTV channels
2500 IGP, 250k BGP
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 19
Summary across all available CRS1 data
UC has negligible impact on MC behavior whether 2500 or 5000 ISIS prefixes
Number of IGP prefixes does not impact SSM convergence
0 100 200 300 400 500 600 700 800 900 1000
1A ACL 400 isis2500bgp250k
1A ACL 800 isis2500bgp250k
1A ACL 4000 isis2500bgp250k
1A ACL 400 isis5000bgp250k
1A ACL 800 isis5000bgp250k
1A ACL 4000 isis5000bgp250k
ms
max of max
median of median
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 20
MPEG Frame Impact from Packet Loss
Competitor systems can take 1sec or MORE to converge 400 (S,G) entries
0%
20%
40%
60%
80%
100%
120%
0 200 400 600 800 1000 1200
Impairment (ms)
% Chance of Lost Frame
I-Frame
P-Frame
B-Frame
100%
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 21
IPMcast QOS Requirements
Network congestion is not a significant impairment contributor
..normally..
BUT it is a necessary safety-net
On-network multicast traffic is well knownFlows, rates, sources..
Access can sycronize/spike“Mother’s day” events
Real-time (VoIP) traffic should not suffer from other traffic events
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 22
Triple-PlayQOS test assumptions
Support 4 classes of service with a strict priority relationship between these classes as follows:
Unicast High > Multicast High > Multicast Low > Unicast Low
ie: Voip > Premium Vid > Broadcast Vid > Access
Full line rate performance is expected for all traffic transmitted in each class when uncongested.
No effects observed on higher class performance due to traffic transmission on a lower class.
No effect on unicast traffic, nor should the unicast traffic effect the multicast traffic.
Congested interface should not affect same multicast flow(s) destined to adjacent uncongested interfaces.
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 23
QOS Test Configuration 2
SPIRENTAX-4000-
Port 2
HPM,LPM
LPU
HPU + HPM + LPM + LPU = 100%HPU + HPM + LPM + LPU > 100%
TenGigE0/0/0/3
TenGigE0/0/0/1
TenGigE0/0/0/0
SPIRENTAX-4000
Port 3
Port 1
CRS-1
TenGigE0/0/0/4 Port 4
TenGigE0/0/0/5 Port 5
TenGigE0/0/0/6 Port 6
HPU
Strict Priority order for droppingHPU > HPM > LPM > LPU
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 24
QOS Test 2 - 1of3
0
1
2
3
4
5
6
7
8
9
1 12 23 34 45 56 67 78 89 100 111 122 133 144 155 166 177 188 199 210 221 232 243
HPU_bitrate(Gb)
HPM_bitrate(Gb)
LPM_bitrate(Gb)
LPU_bitrate(Gb)
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 25
QOS Test 2 - 2of3
0
2
4
6
8
10
12
HPU_bitrate(Gb)
HPM_bitrare(Gb)
LPM_bitrate(Gb)
LPU_bitrate(Gb)
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 26
QOS Test 2 - 3of3
0
2
4
6
8
10
12
HPU_bitrate(Gb)
HPM_bitrate(Gb)
LPM_bitrate(Gb)
LPU_bitrate(Gb)
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 27
QOS Test 2 - Port 4
0
2
4
6
8
10
12
1 20 39 58 77 96 115 134 153 172 191 210 229 248 267 286 305 324 343 362 381 400 419
HPM_bitrate(Gb)
LPM_bitrate(Gb)
QOS profile is maintained on the adjacent interface with zero packet loss of the higher priority traffic.
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 28
QOS Test Configuration 3
SPIRENTAX-4000-
Port 2
HPU, LPM
LPU
HPU + HPM + LPM + LPU = 100%HPU + HPM + LPM + LPU > 100%
TenGigE0/0/0/2
TenGigE0/0/0/1
TenGigE0/0/0/0
SPIRENTAX-4000
Port 3
Port 1
CRS-1
HPU = 55%, LPM = 30%, LPU= 5%HPM step from 10% to 90%
HPM
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 29
QOS Test Configuration 3
SPIRENTAX-4000-
Port 2
HPU, LPM
LPU
HPU + HPM + LPM + LPU = 100%HPU + HPM + LPM + LPU > 100%
TenGigE0/0/0/2
TenGigE0/0/0/1
TenGigE0/0/0/0
SPIRENTAX-4000
Port 3
Port 1
CRS-1
Test parameters: Rate: Data traffic for HPU,LPM and LPU is fixed at 5.5Gb/s, 3.0Gb/s and 0.5Gb/s respectively. HPM traffic follows square wave pattern from 1.0Gb/s for 30secs to 9Gb/s for 20secs to represent bursty HPM traffic
Packet size: 220 bytes for HPU, 1496 for HPM, LPM and LPU
HPM
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 30
QOS Test 3
0
1
2
3
4
5
6
1 23 45 67 89 111 133 155 177 199 221 243 265 287 309 331 353 375 397 419 441 463 485 507
HPU_bitrate(Gb)
HPM_bitrate(Gb)
LPM_bitrate(Gb)
LPU_bitrate(Gb)
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 31
CRS IPMulticast Test Summary
CRS is the IPTV / IPMcast Industry Leader
IPMcast convergence is exceptionally fastAnd improving through constant engineering efforts
No need to chase phantom numbers
QOS performance is unmatched
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 32
Agenda
IPTV Deployments
Impact of Packet Loss on MPEG2 Frames
Network Impairment Contributors
CRS IPMulticast Test Data
Summary
Future Challenges
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 33
IPTV Deployments today
Native IPMulticast performance in the CRS is a driving factor
Mcast PPS
Fan-out
IPMcast convergence
Unicast/Mcast QOS
200 - 1000 (S,G)s is typical
Cable, DSL, and Satellite
The largest is testing 10,000 (S,G)s as its goal
Has chosen native IPMcast over PtMP
High performance of the CRS (exceeded requirements)
Simple to configure, maintain, operate, etc..
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 34
IPTV Deployments Today
Beginning to see the 50ms “requirement” disbandedScalability and stability of CRS/XR
Simplicity of IPMcast
Overlay solutions do not reduce frequency of impairments
Never reaches 0 loss (never really reaches the 50ms goal)
May doesn’t address link-up transitions
Adds excessive network and operational complexity for little gain
Selecting the right platform is the best solution
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 35
Agenda
IPTV Deployments
Impact of Packet Loss on MPEG2 Frames
Network Impairment Contributors
CRS IPMulticast Test Data
Summary
Future Challenges
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 36
Future Challenges
Current IPTV is a value added serviceOn-net injection
PPV or local Advertising Revenue
Walled GardenEdge provider “owns” the customer
Will this last?
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 37
Future Challenges
VoipVideoAccess
Access bandwidth is driven by competition
Access bandwidth rapidly surpassing video bandwidth
Video bandwidth is semi-bounded
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 38
Future Challenges
IPTV works as a Value Added service today
Access bandwidth growth opens up new applications
Over-the-top video is already here - in some form..Joost, MacTV, YouTube, BitTorrent, AMT
More available bandwidth will only improve these applications
DVRs are changing how people watch TV
Consumers don’t care how their DVRs are populated
Will live-TV be relevant in the future?
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 39
Future Challenges
How does a provider say in the food-chain?
Continue to expand content offeringStay ahead of the curve
Open IPMcast transport to off-net contentLook for key strategic content partners
Integrated Directory APICisco/SciAtl
© 2006 Cisco Systems, Inc. All rights reserved. Cisco ConfidentialPresentation_ID 40
Thank You
top related