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IPTV and setting Precedence bit

I'm working with a client on QOS and traffic shaping. Client has a central site with 7206 router and at 11 other remote sites they have 7204vxr. The central site is connected via ATM OC3. The remote sites all have ATM DS3. I'm setting their ATM provisioning for VBR with SCR = 10, PCR = 20, MBS = 32 and on all Remote Routers and I'm traffic shaping with the following commands on all 7204vxr:

interface ATM2/0

> no ip address

> no atm clock INTERNAL

> atm scrambling cell-payload

> atm framing cbitplcp

> no atm ilmi-keepalive

> !

> interface ATM2/0.1 point-to-point

> description Data from BA_7204 to Ed Center

> ip address x.x.x.x

> no ip mroute-cache

> atm pvc 119 15 43 aal5snap

> ntp broadcast client

> ipx network 119

> ip pim sparse-dense-mode

> vbr-nrt 10000 20000 32 ! SCR = 10000 megs, PCR = 20000 megs, MBS = 32

> service-policy output WAN


> class-map Video

> match ip precedence 4


> policy-map WAN

> class Video

> Priority 5000 ! guarantees 5 megs for Video by creating a strict

> priority class and specify the amount of bandwidth

> in kbps of the PVC's bandwidth to be assigned to

> the class.

> class class-default

> fair-queue

Basically, I'm trying to set it such that each DS3 has SCR of 10 megs, SCR of 20 megs, and MBS of 32 since I don't want to oversubscribe the OC3 which is 155 megs. I was told by another engineer that IPTV does not set the precedence bit. So it looks as though I will need to set the precedence bit to 4 manually on the switch the IPTV is directly connected to. Am I right in doing this traffic shaping? Client is currently only using about 5 megs for data on any given DS3. My other question is, if client has IPTV broadcast server connected to say port 4 on a 2950 switch, what commands can I use to set the precedence bit to 4 so that my routers can classify the traffic with the above mentioned router configs. I was looking at the following two ways, but not sure which would work?

access-list 1 permit

class-map videoclass

match access-group 1

policy-map videopolicy

class videoclass

set ip dscp 32

interface fastethernet0/1

service-policy input videopolicy

or would you use the following commands instead

interface fastethernet0/1

! Enter interface configuration mode, and specify the ingress interface.

mls qos cos 4


Frequent Contributor

Re: IPTV and setting Precedence bit

The first configuration example should work for what you are trying to accomplish.

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