11-07-2011 04:44 AM - edited 03-07-2019 03:15 AM
So we ran into an interesting issue today, and hoping someone might be able to confirm my assumptions / It'll help someone else out if they come across it.
By default the linecards/system use only 2 egress queues for the 32 port M1 cards.
Which really doesn't line up with what wanted so we modify the config on the default vdc to the following.
class-map type queuing match-any 1p7q4t-out-pq1
match cos 5
class-map type queuing match-any 1p7q4t-out-q2
match cos 7
class-map type queuing match-any 1p7q4t-out-q3
match cos 6
class-map type queuing match-any 1p7q4t-out-q4
match cos 3
class-map type queuing match-any 1p7q4t-out-q5
match cos 2
class-map type queuing match-any 1p7q4t-out-q6
match cos 4
class-map type queuing match-any 1p7q4t-out-q7
match cos 0
class-map type queuing match-any 1p7q4t-out-q-default
match cos 1
Create the relevant policy-map which sets the priority queue and bandwidth requirements for each queue/class
Apply the policy map to the interfaces that we wanted.. Viola, everything works..
Well actually no, the system basically started dropping packets on the egress (output discards) on all the ports that didn't have the new policy applied to them.
Now we can't create custom class maps, we have to use the system default ones, and then modify them suit (match cos statements)
It's my assumption, that once we modify these default class maps, it's also being applied to the default policy
Which reads as follows - sh queuing int e x/x
Service-policy (queuing) output: default-out-policy policy statistics status: enabled Class-map (queuing): out-pq1 (match-any)
priority level 1 queue-limit percent 16 queue dropped pkts : 0
Class-map (queuing): out-q2 (match-any)
queue-limit percent 1 queue dropped pkts : 0
Class-map (queuing): out-q3 (match-any)
queue-limit percent 1 queue dropped pkts : 0
Class-map (queuing): out-q-default (match-any)
queue-limit percent 82 bandwidth remaining percent 25 queue dropped pkts : 0
By modifying the default queues it's affected the default egress policy-map, and in order to function correctly, a custom default list needs to be setup.
With the default egress policy, anything not in the above 4 queues gets dropped.
Few things.
Cheers
11-09-2011 05:32 AM
No one?
02-02-2012 12:08 PM
Hi James.. interesting post, and I was working on similar situation:
Configured queue-limit ratios
queue-limit ratios: 78[1p7q4t-out-q-default] 1[1p7q4t-out-q2] 1[1p7q4t
-out-q3] *1[1p7q4t-out-q4] *1[1p7q4t-out-q5] *1[1p7q4t-out-q6] *1[1p7q4t-out-q7]
16[1p7q4t-out-pq1]
If you look at queues 2, 3, 4,5 - they are at 1 %.. I really dont know the correlation of class-maps to the drop packets output that you showed above. For us we are getting tail drops at queue4, because COS 3 is mapped directly to queue 4 (which should not be the case). COS 0-4 should normally map to default class, but it wasnt
Hope this helps.
Regards
Raj
02-26-2018 05:33 AM - edited 02-26-2018 05:34 AM
Hi James.
Nexus 7000 Queuing
Please find the configuration guide in below link.
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