QOS clarifications

[adamgibs7]

Dear Experts

i want to apply QOS for my Cisco video endpoint which is registered on Cisco cloud, i have the below setup of my organization.

Access switch---->Core---->Internal  Firewall----> Perimeter Firewall--->ADSL Router---> ISP

i want to reserve bandwidth for outgoing calls and receiving call on this endpoint,

please confirm to me the below points for QOS.

1. The qos will be applied on the internet router
2. i have to classify the IP address of the video endpoint and reserve by the bandwidth command 4 Mbps , please correct me by bandwidth command or priority command and i can apply as an service policy output on the ADSL interface ?? or a bandwidth and priority command are only applied on the input interface 
3. For Outgoing calls i can classify by IP address of video endpoint to unknown destination but for receiving calls to my endpoint from Cisco cloud how i can classify them.
4. Please advice a small configuration that will help me to understand.

[Joseph W. Doherty]

The video in question is for video conferencing, not video streaming? QoS if often more critical for the former. However, for either, although you probably most likely want QoS on the path's bottleneck, any other device that has an oversubscribed interface or link along the path should have QoS too.

I.e. for #1, if Internet router is primary bottleneck, generally that's the most critical to have QoS applied on it, but again, more network devices along the path, even possibly all, might need QoS to guarantee end-to-end performance.

For #2 the ADSL interface is Ethernet? Generally most Cisco routers support QoS on most of their interfaces.

For ADSL, "up" bandwidth is often less then the physical port's bandwidth, so you need to configure a "shaper" to insure QoS works correctly with the actual available bandwidth.

Neither the bandwidth or priority commands "reserve" bandwidth, they both insure that there's a minimum guaranteed amount of bandwidth. Which of the two commands to use depends on what kind of video you're using and what other QoS needs you might have. Both commands can only be used for egress. On the latter point, you won't really be able to reserve or guarantee bandwidth, for traffic, inbound. (When you control the complete path, one side's inbound is the other side's outbound, but with the Internet, that likely not true in this case. In other words, with involvement of the Internet, QoS, alone, might be unable to guarantee the performance your video will require.)

For #3, you can classify your video point's traffic using either a source or destination address.

For #4:

ip access-list extended video-IPs
permit ip host x.x.x.x any
permit ip any host x.x.x.x

class-map match-any video
match access-group name video-IPs

policy-map QoS
class video
bandwidth (or priority) 4000

interface x
service-policy output QoS

If a shaper is needed (add/change):

policy-map shaped-QoS
class class-default
shape average 4000000
service-policy QoS

interface x
service-policy output shaped-QoS

[adamgibs7]

Dear Joseph

(When you control the complete path, one side's inbound is the other side's outbound, but with the Internet, that likely not true in this case. In other words, with involvement of the Internet, QoS, alone, might be unable to guarantee the performance your video will require.)

by the above words you mean to say for the incoming traffic ?? m i correct if we are controlling for the outbound traffic for inbound we might not be having the control on it.

Neither the bandwidth or priority commands "reserve" bandwidth, they both insure that there's a minimum guaranteed amount of bandwidth. Which of the two commands to use depends on what kind of video you're using and what other QoS needs you might have. Both commands can only be used for egress.

the other Qos is browsing traffic and  i want to give minimum bandwidth to video conferencing traffic. so what command should be used.???

Thanks

[Joseph W. Doherty · Accepted solution]

"by the above words you mean to say for the incoming traffic ?? m i correct if we are controlling for the outbound traffic for inbound we might not be having the control on it."

Mostly ingress traffic, but remember, generally there's no QoS support within the Internet.

"the other Qos is browsing traffic and i want to give minimum bandwidth to video conferencing traffic. so what command should be used.???"

Well, generally you don't want to just provide minimum bandwidth to video conferencing traffic, you want to provide is the bandwidth it requires. Otherwise, it tends to "fail".

As to "browsing traffic", placed into the "class-default", using FQ, usually works very well for it.

E.g.:

policy-map QoS
class video
bandwidth (or priority) 4000
class-default
bandwidth remaining percent 100
fair-queue