Nortel Networks 5510, 5520, 5530 4. Queue Sets

Filters and QoS Configuration for ERS 5500

Technical Configuration Guide v2.0 NN48500-559

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External Distribution

4. Queue Sets

Prior to software release 4.0, the Ethernet Routing Switch 5500 supporte d a single queue set with

eight queues, one absolute queue and seven WRR queues.

With the introduction of software release 4.0, eight different queue sets where m ade available.

Each queue set has different characteristics in regards to number of queues and service weights

allowing the user to select a queue set based on the user’s particular n eeds. With eight queue

settings and three resource sharing options, the Ethernet Routing Switch 55 00 supports a total of

24 different queues and buffer setting combinations. Prior to mak ing any changes to the egress

queue, the buffer resource sharing feature must be enabled.

Resource Sharing

The three (3) possible resource sharing settings in version 4.0 or greater software release are

regular, large, and maximum. These settings allow the user to change the am ount of buffer

which can be allocated or shared to any port. Note that the switch mus t be rebooted if any

changes are made.

Table 4: Ethernet Routing Switch 5500 Resource Sharing

Setting Description

Regular

1 port may use up to 16% of the buffers for a group of 12 ports.

Large

1 port may use up to 33% of the buffers for a group of 12 ports.

Maximum

1 port may use 100% of the buffers for a group of 12 ports.

Resource Sharing Commands

• 5520-24T-PWR(config)# qos agent buffer <large | maximum | regular>

The qos agent buffer <regular | large | maximum > command allo ws the user to specify

the level of resource sharing on the switch. This parameter is global and requires a reset

to activate a change. This command is in the CLI priv-exec mode.

• 5520-24T-PWR(config)# default qos agent buffer

The default qos agent buffer command sets the switches agent buff er back to a default

setting of regular. In order for this command to take affect, a reset of the s witch must

occur. This command is in the CLI priv-exec mode.

Resource Sharing Recommendations

Nortel Networks recommends you use the default resource-sharing setti ng of regular. If

you change the setting, the resulting performance may increase for som e ports, and at

times, decrease for other ports.

Generally speaking, smaller buffers achieve lower latency (RT T) but reduce the throughput ability

which is better for VoIP etc. and sensible jitter application.

You should use the Maximum resource sharing setting:

• If you are using your 5520 for big file transfers (like backup of servers)