I want to implement QoS to improve voice quality on our network. We are a Cisco shop. The switches are 2950's and 3750's and the routers used ranges from 2800's to 3845's. Should I implement AutoQoS or configure QoS manually? If Autoqos is suggested, what IOS on the switches and routers supports this? Can you send sample configs? I'm new to QoS. TIA.
AutoQoS or not? Well, the idea is to avoid the need to build and maintain your own QoS model. In principal, fine idea. Believe there are different flavors of AutoQoS, but believe all will prioritize voice. Personally my QoS experience predates AutoQoS, so I'm biased, and I find the later variants overly complex, at least on routers. Believe you can customize what they generate, but if your willing to do that, why not make you own (doesn't have to be complex for routers - see below).
Usually, all you need to do in insure the voice traffic is expedited, without drops, and its control traffic isn't dropped. Assuming your voice packets have a marking of DSCP EF, something as simple as this on your WAN routers often works well:
(syntax might be off - also syntax various between some IOS versions)
match ip DSCP EF (assuming phones tag the packet, or you'll need to tag it)
priority percent 50
interface serial 0
service policy outbound CBWFQ
The above places voice traffic in what's known as LLQ (low latency queue), if present it goes first. Everything else alternates between all the flows.
On 2950 or 3750, service policies for outbound are not supported, but you can accomplish something functionally similar except the FQ for everything else, above, isn't available. On those platforms you might need to place the voice control traffic in it's own outbound class. Here is where you might want to try AutoQoS.
Since WAN links usually have less bandwidth, and higher latency, QoS is often critical. For LAN links, there often is so much excess bandwidth that you won't see sustained congestion, or nothing but short term transient congestion. If the latter is true in your environment, you can get by without QoS, but at risk.
This document gives several answers on frequently asked questions for PFRv3 channel state behavior.
Q1: What are all the channel operational states from a BR (border role) perspective and what are the rules/conditions to be in each st...
The need was to reach an host inside a LAN through a VPN connection managed by the LAN gateway (Cisco 1921).
The LAN gateway performs NAT and there was a dedicate nat rule for the host i wanted to reach through VPN.
I couldn't connect to the hos...
We have 3 identical switches configured by someone else and would like to claim some of the Gigabit ports(G1/G2/G3/G4) for use on servers. When we try to change the wiring and configuration, we run in to connectivity issues. Attached is a des...