Hi
Question about QOS on ASR1K series.
It supports only egress queuing. So service policies dealing with shaping are usable only on output.
In a design with asymetric bandwidth between interfaces (1Gbits to 10Gbits or 10Gbits to LAG 2x10Gbits for example), how to deal with the difference without limiting to the lower bandwitch ?
For example, let's say an ASR with:
- one interface ge-0/0/0 1G to service provider
- one Etherchannel Po1 2x1G to core network with 802.1Q sub-interfaces Po1.10 / Po1.20 / Po.30
There are at least three main data paths:
Path1) ge-0/0/0 to Po1 = 1G to 2x1G.
Path2) Po1 to ge-0/0/0 = 2x1G to 1G
Path3) Po1.x to Po1.y = 2x1G (in fact multiples 1G to 1G due to load balancing on LAG)
On path1, it's fine to shape around 1G to deal with ingress ge-0/0/0 bandwitdh.
On path2, it's fine to shape around 1G to deal with egress ge-0/0/0 bandwitdh.
On path3, we may shape around 2G to deal with egress Po1 bandwitdh but by default, the service policy applied on output does'nt care about input interface. So the shaping around 1G applied for path 1 , we'll also apply to path3 then it'll limit the overall Etherchannel bandwidth.
So I've got to questions:
- is it requested and feasible to separate two service policies on output for the Port-channel interface ? one by taking care of input-interface to shape lower to the ingress bandwidth of the slower path and the other to the overall Etherchannel bandwidth
- about Etherchannel interfaces, documentation states that we can apply the MQC service policy to the Etherchannel itself. Fine, but if we design the policy with the overall bandwitch in mind, what happens if the Etherchannel loose a member interface ? In my example, we'll fail to 1G of bandwith available but with a 2G policy. So would it be more accurate to apply old style agregate QOS on physical interfaces members ?
Agregate Etherchannel OQS (last evolution): https://www.cisco.com/c/en/us/td/docs/routers/ios/config/17-x/qos/b-quality-of-service/m_aggregate_etherchannel_quality_of_service.html
Old Etherchannel QOS: https://www.cisco.com/c/en/us/td/docs/routers/ios/config/17-x/qos/b-quality-of-service/m_qos-eth-int-1.html#GUID-95630B2A-986E-4063-848B-BC0AB7456C44
Regards
