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priority queueing on a 3750

According to sw feature navigator 3750 supports priority queuing - although it didn't actually display the exact image I'm running, c3750- advipservicesk9-mz.122-25.SEE4.bin

Set this up using this doc as a guide -

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Well, according to these show commands it doesn't appear to be working. Lots of traffic has passed over this link destined for the ip in question, but, no acl hits or queue stats that show what I'd expect. This queue-list only contains specfication for low and default queues. Yet according to these show commands the low priority isn't even being used, the high queue is, and on the interface itself none of them are. Something's not right.

sh run int vlan 7 Building configuration...

Current configuration : 257 bytes ! interface Vlan7 ip address 1x.x.x.x ip ospf authentication message-digest ip ospf message-digest-key 1 md5 7 0216027824565A314A ip ospf network point-to-point ip ospf priority 100 priority-group 1

#sh queueing priority

Current DLCI priority queue configuration:

Current priority queue configuration:

List Queue Args

1 low protocol ip list 101

sh access-list 101

Extended IP access list 101

10 permit ip any host 172.22.1.18

sh queueing interface vlan 7 Interface Vlan7 queueing strategy: priority

Output queue utilization (queue/count) high/6143 medium/0 normal/306331 low/0

sfo-l3sw-01#sh int vlan 7

Vlan7 is up, line protocol is up

Hardware is EtherSVI, address is 0011.20d1.8dcf (bia 0011.20d1.8dcf)

Description: Opt-E-Man link

Internet address is x.x.x.x

MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops:

0

Queueing strategy: priority-list 1

Output queue (queue priority: size/max/drops):

high: 0/20/0, medium: 0/40/0, normal: 0/60/0, low: 0/80/0

Reply to
linguafr
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The doc that you have is for router configuration. The 3750 is a L3 Switch - there is a difference. Use this document instead:

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FYI... The idea behind the queueing on a switch is that there is much more throughput and a strict priority queue is not usually needed. The switch will use a WRR giving more priority to the appropriate classes of traffic (this needs to be configured). If you still need a strict priority queue, you can use the priority-queue out command.

Hope that helps,

Jim

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Reply to
Scooby

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a few other things....

the priority Q is disabled by default on the 3750 - you need to turn it on AFAIR it is a per interface setting.

you get at the priority stats with "show mls qos......" commands.

by default any existing markings on packets are ignored - i use DSCP so need "mls qos trust dscp" on any port where the markings coming in affect the packet.

if you use policy / policing then any trust statements need to be embedded in the policy - otherwise the switch takes the command OK, but ignores 1 or the other.....

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Reply to
stephen

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