Qos相关配置

　　Configuraton

　　*FIFO

　　(config-if)#FIFO

　　*weighted fair

　　(config-if)#fair-queue{congestive-discard-threshold}

　　*Priority

　　(config-if)#priority-group group_number(1-16)

　　(config)#priority-list list-number protocol protocol-name {high | medium | normal | low} queue-keyword

　　keyword-value

　　list-number interface interface-type interface-number {high | medium | normal | low}

　　(config)#priority-list list-number default {high | medium | normal | low}

　　*optional commands

　　!command to change the max number of packets in each queue.

　　(config)#priority-list list-number queue-limit high-limit medium-limit normal-limit low-limit

　　!default 20 40 60 80

　　!queue-keyword values

　　fragmens-->number of fragments

　　gt-->port num

　　lt-->port num

　　list--->access list

　　tcp-->port num

　　udp-->port num

　　*Custom

　　(config-if)#custom-queue-list list_number(1-16)

　　(config)#queue-list list-number protocol protocol-name {high | medium | normal | low} queue-keyword keyword-value

　　(config)#queue-list list-number interface interface-type interface-number queue-number

　　(config)#queue-list list-number default queue-number

　　-optional commands

　　!specify the max number of packets for a particular queue (limit-number 0 - 32,767)

　　(config)#queue-list list-number queue queue-number limit limit-number

　　!if max number of packets are set too low you will drop the excess traffic!!!!

　　!default limit-number is 20

　　(config)#queue-list list-number queue queue-number byte-count byte-count-number

　　!default byte count is 1500

　　*debug commands

　　show queueing

　　show queueing {int | custom | priority | fair }

　　show interfaces

　　Compression

　　One of the most important points in compression theory is that there exists a theoretical limit, known as Shannon's Limit, to how much a given source of data can be compressed. Beyond that point, it is impossible to reliably recover compressed data.

　　Compression is not a bandwith replacement only a temporary fix!

　　You should not compress:

　　Already compressed data

　　Encrypted data

　　High speed links

　　Compression is typically either a cpu or memory intensive opreation and must be preformed on both ends of the connection.

　　Types of compression

　　Link compression (also known as per-interface compression, mainly point to point links because the packet is non-routable once compressed)

　　Payload compression (also known as per-virtual-circuit compression, can be used any situation)

　　TCP header compression (used when you have lots of small ip packets)

　　Three types of link compression

　　predictor - memory intensive

　　stac - cpu intensive

　　mppc- microsoft point-to-point compression- used in tunneling ppp across a virtual connection (PPPTP- Point-to-Point Tunneling Protocol)

　　(config-if)#compress {predictor | stac | mppc}

　　Payload compression

　　used mainly in

　　Frame relay

　　SMDS

　　ATM

　　(config-if)#compress payload-compress

　　TCP header compression

　　used mostly in PPP connections

　　(config-if)#ip tcp header-compression