09-25-2013 06:08 AM - edited 03-04-2019 09:08 PM
Hello, we have HQ with 5 remote sites and videoconference on our old Polycom videoconference bridge worked fine. The new RMX Polycom videoconference bridge sends bursts up to 80% of it's configured bandwidth and it's creating video issues (blocks on the TV screen).
The new Polycom bridge is configured to do HD using H264 high profile @ 512 kilobits per seconds.
What is the uptimum VBR-NRT values for videoconferencing? Our WAN provider is suggesting vbr-nrt 2442 2442 1 but that does not seem right for a T1.
CURRENT: vbr-nrt 1792 1792 1
TEST: vbr-nrt 1792 1692 100 (IT'S BETTER BUT STILL NOT ACCEPTABLE)
configs:
HQROUTER3725-OC3>
class-map match-all llq-video
match access-group 101
policy-map llq
class llq-video
priority 768
!
interface ATM1/0
description SIP ID XXXXXX/000036/UCN/001
mtu 1500
no ip address
atm ilmi-keepalive
pvc 0/16 ilmi
ilmi manage
!
!
interface ATM1/0.101 point-to-point
description 1536K circuit ID JXXXXXXXXXX
ip address X.X.X.X 255.255.255.252
no ip mroute-cache
pvc 1/136
vbr-nrt 1792 1792 1
encapsulation aal5snap
service-policy output llq
!
!
interface ATM1/0.102 point-to-point
description 1536K circuit ID XXXXXXXXX
ip address X.X.X.X 255.255.255.252
no ip mroute-cache
pvc 1/102
vbr-nrt 1792 1792 1
encapsulation aal5snap
service-policy output llq
!
!
interface ATM1/0.103 point-to-point
description 1536K circuit ID XXXXXXXXX
ip address X.X.X.X 255.255.255.252
no ip mroute-cache
pvc llq 1/103
vbr-nrt 1792 1792 1
encapsulation aal5snap
service-policy output llq
!
!
interface ATM1/0.104 point-to-point
description 1536K circuit ID XXXXXXXXX
ip address X.X.X.X 255.255.255.252
no ip mroute-cache
pvc 1/104
vbr-nrt 1792 1792 1
encapsulation aal5snap
service-policy output llq
!
!
interface ATM1/0.105 point-to-point
description 1536K circuit ID XXXXXXXXX
ip address X.X.X.X 255.255.255.252
no ip mroute-cache
pvc llq-wpg 1/137
vbr-nrt 1792 1692 100
encapsulation aal5snap
service-policy output llq
!
!
*************************************
REMOTEROUTER1721-T1>
class-map match-all video
match access-group 101
policy-map videoqos
class video
priority 768
!
!
interface Serial0/0
description Allstream SIP ID 08/XXXXXXXXX/UCN/001 - 1536K
bandwidth 1536
no ip address
encapsulation frame-relay
ip route-cache flow
no ip mroute-cache
no fair-queue
frame-relay traffic-shaping
!
interface Serial0/0.19 point-to-point
description 1536K PVC WPG to Ottawa - IP
bandwidth 1536
ip address X.X.X.X 255.255.255.252
ip nbar protocol-discovery
ip pim dense-mode
snmp trap link-status
frame-relay class cirb
frame-relay interface-dlci 23 IETF
!
map-class frame-relay cirb
frame-relay cir 1536000
frame-relay mincir 1536000
service-policy output videoqos
09-25-2013 10:48 AM
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Posting
If your video improved when you set a lower SCR, I would suspect the ATM PVC is overrunning the frame-relay T1. Once again set PCR and SCR to same values, but try other lower values (perhaps in 50K increments). Unfortunately as ATM overhead varies per packet, there's no 1:1 conversion.
What you can also try is reducing hardware FIFO queues, both on the ATM and frame-relay interfaces. Set smaller or minimum tx-ring-limits.
Also on the frame-relay size, don't muck with CIR shaping; just use full interface bandwidth. (If CIR is a real issue, increase it so it isn't.)
Are you seeing any drops on your LLQ? If so, try increasing its bandwidth allocation.
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