QoS for Multicast Traffic

[Louey]

Hi all,

I need some help building a QoS Strategy for Multicast video streams sent from four different sources to four different groups via WAN links.

The sources are in the same site, sending to 8 different sites. Generated traffic from sources is 110 Mbps that the customer want to transmit, but the WAN links are only 100 Mbps bandwith. The most important trafic where latency would not be acceptable is the source 1 and source 2 traffic which is 55 mbps. The source 3 is 17,5 Mbps and source 4 37,5 Mbps.

What action can I apply to source 1 and 2 so they will be Assured 55 Mbps, and what can I do for source 3 and 4 to give priority to source 3 and make best effort for source 4.

Can someone help me with that ?

Regards,

[marce1000]

 - FYI : https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus5000/sw/qos/521_n1_1/b_5k_QoS_Config_521N11/b_5k_QoS_Config_521N11_chapter_0111.pdf

                     Look at paragraph  : QoS for Multicast Traffic

 M.

[Joseph W. Doherty]

As QoS features vary by platform, and sometimes by IOS version, what platform (and its IOS version) will be managing the 100 Mbps egress?

Multicast video is the only traffic that would be on this WAN link?

Are the bandwidth specifics you've provided, peaks or averages?

Only based on the information in your OP, something like the following (logical) CBWFQ policy should meet your requirements:

policy-map logical
class-map sources1and2
priority 55000000 'LLQ for minimal latency (and minimal jitter) - assuming this LLQ using implicit policer
class-map source2
bandwidth 17500000
class-map default
bandwidth 27500000

or perhaps even better:

policy-map logical
class-map sources1and2
priority 55000000
class-map source2
bandwidth 4400000 'or bandwidth remaining percent 99 - larger bandwidth allocation, basically, prioritizes this class over BE
class-map default
bandwidth 1000000 'or bandwidth remaining percent 1

[Louey]

Hi Joseph,

Thanks a lot for your answer.

For question one, I dont know the actaul equipements, all I know that they are old one but support QoS policies.

Second answer, Multicast is not the only trafic, there is SNMP trafic and control plane trafic (OSPF, PIM) (not sure if I should count this one).

The bandwith I've specified, are addition of Video HD/SD bandwidth trafic so I guess this is average Bandwidth.

Should I use a class for control-plane trafic (SNMP and OSPF) and apply a bandwith policy to it above the class-default ?

policy-map logical
class-map sources1and2
priority 55000000 'LLQ for minimal latency (and minimal jitter) - assuming this LLQ using implicit policer
class-map source2
bandwidth 17500000

Class-map control

bandwidth 500000
class-map default
bandwidth 27000000

What do you think about that ?

[Joseph W. Doherty · Accepted solution]

Sure, if you have other traffic you need to insure bandwidth for, you can define another class for it.  Or conversely, you use the default class for all the traffic, and put source 4 into its own class.  If you do the latter, FQ in class-default will "protect" most flows from other bandwidth intensive flows (within the same class).

If, indeed, you video bandwidths are based on an average, you can quickly run into performance issues, with latency, jitter, drops, because, I believe, most video codecs are variable bit rate.  To insure variable bit rate video, the performance desired, you need to allocate bandwidth for peak usage.  (Remember, even if you allocate for peak usage, unused bandwidth will be available for other traffic.  What you want to avoid, is video traffic bursting above its average consumption and not being able to acquire, immediately, the bandwidth it needs.)