Borderless campus Qos and IP phones

[Hao Hu]

Hi,
 
After reading the borderless campus qos recommendation for this document, I'm a bit confused by the settings on 
on the classification of voip RTP traffic. 
 
 http://www.cisco.com/en/US/docs/solutions/Enterprise/Campus/Borderless_Campus_Network_1.0/BN_Campus_QoS.html
 
 
cr22-4507-LB(config)#ip access-list extended MULTIMEDIA-CONFERENCING

cr22-4507-LB(config-ext-nacl)# remark RTP

cr22-4507-LB(config-ext-nacl)# permit udp any any range 16384 32767

cr22-4507-LB(config-ext-nacl)#ip access-list extended SIGNALING

cr22-4507-LB(config-ext-nacl)# remark SCCP

cr22-4507-LB(config-ext-nacl)# permit tcp any any range 2000 2002

cr22-4507-LB(config-ext-nacl)# remark SIP

cr22-4507-LB(config-ext-nacl)# permit tcp any any range 5060 5061

cr22-4507-LB(config-ext-nacl)# permit udp any any range 5060 5061

....... 

 Class-map
  
 
cr22-4507-LB(config)#class-map match-all VVLAN-SIGNALING




cr22-4507-LB(config-cmap)# match ip dscp cs3








cr22-4507-LB(config-cmap)#class-map match-all VVLAN-VOIP




cr22-4507-LB(config-cmap)# match ip dscp ef 








cr22-4507-LB(config-cmap)#class-map match-all MULTIMEDIA-CONFERENCING




cr22-4507-LB(config-cmap)# match access-group name MULTIMEDIA-CONFERENCING








cr22-4507-LB(config-cmap)#class-map match-all SIGNALING




cr22-4507-LB(config-cmap)# match access-group name SIGNALING








.....
 
policing 
cr24-3750-LB(config)#policy-map Phone+PC-Policy




cr24-3750-LB(config-pmap)# class VVLAN-VOIP




cr24-3750-LB(config-pmap-c)#  police 128000 8000 exceed-action drop




cr24-3750-LB(config-pmap-c)# class VVLAN-SIGNALING




cr24-3750-LB(config-pmap-c)#  police 32000 8000 exceed-action drop




cr24-3750-LB(config-pmap-c)# class MULTIMEDIA-CONFERENCING




cr24-3750-LB(config-pmap-c)#  police 5000000 8000 exceed-action drop




cr24-3750-LB(config-pmap-c)# class SIGNALING




cr24-3750-LB(config-pmap-c)#  police 32000 8000 exceed-action drop




....
marking
 
cr22-3750-LB(config)#policy-map Phone+PC-Policy




cr22-3750-LB(config-pmap)# class VVLAN-VOIP




cr22-3750-LB(config-pmap-c)#  set dscp ef




cr22-3750-LB(config-pmap-c)# class VVLAN-SIGNALING




cr22-3750-LB(config-pmap-c)#  set dscp cs3




cr22-3750-LB(config-pmap-c)# class MULTIMEDIA-CONFERENCING




cr22-3750-LB(config-pmap-c)#  set dscp af41




cr22-3750-LB(config-pmap-c)# class SIGNALING




cr22-3750-LB(config-pmap-c)#  set dscp cs3




cr22-3750-LB(config-pmap-c)# class TRANSACTIONAL-DATA




cr22-3750-LB(config-pmap-c)#  set dscp af21




cr22-3750-LB(config-pmap-c)# class BULK-DATA




cr22-3750-LB(config-pmap-c)#  set dscp af11




cr22-3750-LB(config-pmap-c)# class SCAVENGER




cr22-3750-LB(config-pmap-c)#  set dscp cs1




cr22-3750-LB(config-pmap-c)# class DEFAULT




cr22-3750-LB(config-pmap-c)#  set dscp default



 
 
 My questions are
 
 1. Will this setting put the RTP traffic from a softphone behind the Cisco IP phone into the
MULTIMEDIA-CONFERENCING class, which was set to the DSCP af41 instead of EF eventually?
2. What if the IP phone  on this switchport is a non-cisco IP phone. (e.g. Avaya IP Phone.)
if the port is still configured as a conditional-trust port, will the same thing happen that the Avaya ip phone's 
voip traffic will be set to default dscp value at the ingress first before it was classified by class 
MULTIMEDIA-CONFERENCING and set to DSCP af41 instead of ef?

Is there any limitation of this settings?

Kevin

  
 
 

[acampbell]

1) This policy would be applied to your switch port as an inbound policy on ingress.
The data will arrive serially at the port and each IP packet will inspected and
treated as per the policy.
The switchport has not control over the order of packet arrival. Therfore the ingress
packets will be treated in a first come first served fashion no matter whether they
are from the actual phone or any device behind it.

2) The AVAYA phone will not be sending rtp packet with udp port range 16384-32767 as these
are Cisco IPT values but can be matched as DHCP EF (46). For signalling it is best to ask
the AVAYA switch person to change thesignalling DSCP to CS3 (24) for traversing Cisco network kit.
This allows you to either just trust the DSCP
on a port or use the policy map.

!
interface fas 0/21
desc *** AVAYA PHONE & PC ***
mls qos trust dscp
queue-set 1
srr-queue bandwidth share 1 30 35 5
priority-queue out
!

The bandwidths should be similar between Cisco & Avaya phones.

HTH
Alex

[Hao Hu]

Thank you acampbell for your answers.

Actually my question is more on the marking part.

let's  say a PC behind a 3750 switch port, so switchport can't trust the DSCP setting from the PC.

Then CIPC rtp stream DSCP will be set to default.

Am I correct that once the CIPC RTP traffic hit the ingress, it will be caught by MULTIMEDIA-CONFERENCING class instead of

VVLAN-VOIP class and the DSCP will be set to AF41 while DSCP EF is preferred setting for RTP?