The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
I see the "match ip dscp af21" , but I see no ACL's that tells it what traffic it should match.
That's because the match statement supports certain matching without using ACLs. In this case, it examines the ToS byte, and if the value is a DSCP AF21, it matches.
Could someone explain to me how the equipment knows what traffic is voip or video?
In your policies, it doesn't really know what traffic is VoIP or video. Your policy is just looking at certain ToS settings; this is assuming your VoIP and video traffic is already (correctly) tagged/marked.
As Joseph has already mentioned, you don't need to specifically configure an ACL to match for marking.
CoS or Class of Service values, are used on 802.1q trunks. This is because, when a switch tags a frame with 802.1q vlan tag, which includes within it a field called 802.1p for User Priority. This is where the CoS values come into play.
You can also specify an ACL, and have it mark frames based upon that value.
Also, within each IPv4 packet, there is a field called the ToS byte. This ToS byte is 8 bits (as you would expect)
Ths is where you can mark traffic with the following values, COS, DSCP, and IPP.
In the old days, you could only use 3 bits for marking, so this would give you 8 levels of marking.
So after a while, people realised we needed more ways to mark traffic, and decided to use 6 bits for marking. This is where the
ToS byte comes into play. You can have DSCP, COS, and IPP values.
COS, is backwards compatible with IPP, and COS uses the first 3 bits, and the last 3 are 000.
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...