April, 2004 Configuring QoS on the OmniStack 6300 Table of Contents 1. Port based rate limiting ........................................................................................................ 2 Example ...............................................................................................................................................................2 Limitation..............................................................................................................................................................2 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................2 2. Queue mode........................................................................................................................ 2 Example ...............................................................................................................................................................2 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................3 3. Priority CoS (Class of service)............................................................................................. 3 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................3 3.1 802.1p Priority (tagged packets)........................................................................................ 3 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................3 3.2 Default priority / Default 802.1p (untagged packets).......................................................... 3 Note......................................................................................................................................................................4 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................4 3.3 Mapping CoS value to egress priority queue ..................................................................... 4 Limitation..............................................................................................................................................................4 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................4 3.4 IP precedence Priority (IP packets) ................................................................................... 5 Limitation..............................................................................................................................................................5 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................5 3.5 IP DSCP Priority (IP packets) ............................................................................................ 6 Limitation..............................................................................................................................................................7 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................7 3.6 ACL Priority (CoS ACL) ..................................................................................................... 7 Example ...............................................................................................................................................................7 Limitation..............................................................................................................................................................7 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................8 4. ACL Marker: 802.1p, ToS, Dscp stamping .......................................................................... 8 Example ...............................................................................................................................................................8 Limitation..............................................................................................................................................................9 Note......................................................................................................................................................................9 Issue.....................................................................................................................................................................9 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ............................................................................9 5. ACL...................................................................................................................................... 9 Precedence........................................................................................................................................................10 ACL masks.........................................................................................................................................................10 Note....................................................................................................................................................................11 Limitations..........................................................................................................................................................11 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ..........................................................................11 5.1 Ip Standard ACL .............................................................................................................. 11 5.2 IP extended ACL ............................................................................................................. 12 5.3 Mac ACL.......................................................................................................................... 12 6 Service Policy, Class-Map and Policy-Map ........................................................................ 13 Class-Map: .........................................................................................................................................................13 Policy-Map: ........................................................................................................................................................14 Internal priority for traffic ....................................................................................................................................14 Service-Policy: ...................................................................................................................................................14 ALC masks.........................................................................................................................................................14 Limitations..........................................................................................................................................................15 Issues.................................................................................................................................................................15 Interoperability with OmniSwitch 6624/6648 7700/7800 8800 ..........................................................................15 Examples ...........................................................................................................................................................15 Configuring QoS on OmniStack 6300 The purpose of that document is to detail the QoS features explained in the "OmniStack 6300-24 User Guide" Please refer to the user guide for more information. The document will go through the following features: 1. "Port based" rate limiting 2. Queue mode 3. Class of Service and priority queues 4. ACL marker: 802.1p, ToS, DSCP stamping on egress packets 5. ACL 6. "Flow based" QoS using Service Policy, Class-Map and Policy-Map 1. Port based rate limiting Bandwidth shaping is configurable on an interface basis. You can shape incoming traffic for an interface to 10Mbps with the "rate-limit input 10 " interface command. You can shape outgoing traffic for an interface to 20Mbps with the "rate-limit output 20 " interface command. The granularity of the bandwidth is 1Mbps. Example To set ingress shaping to 10Mbps on interface 1/1 and set egress shaping to 20Mbps on interface 1/2 Console(config)#interface ethernet 1/1 Console(config-if)# rate-limit input 10 Console(config-if)# exit Console(config)#interface ethernet 1/2 Console(config-if)# rate-limit input 20 Console(config-if)# exit Limitation By definition, shaping is done on an interface basis; all traffic for that interface will be shaped. In order to make a flow based rate limiting rule, the user has to set a "Service Policy". Interoperability with OmniSwitch 6624/6648 7700/7800 8800 The OmniSwitch 6624/6648 7700/7800 8800 switches do not have a port based rate limiting concept. They use the "policy rules" to make the bandwidth shaping for traffic matching the "policy conditions". They do a "flow based" rate limiting. OmniSwitch 6300 can do both "port based" rate limiting and "flow based" rate limiting. 2. Queue mode The switch has 8 priority queues per egress port. You can configure the queue mode to a strict or a Weighted Round-Robin (WRR): WRR (default): shares bandwidth at the egress ports by using scheduling weights 1 2 4 6 8 10 12 14 for queues 0 through 7 respectively; the higher the weight, the higher the bandwidth for that queue Strict: services the egress queues in sequential order, transmitting traffic in the higher priority queues before servicing any lower priority queues The queue mode is set for the entire switch. All interfaces are either in a strict mode or a WRR mode. However, on WRR mode, the weights are configurable on an interface basis. Since the queues are linked to the egress port, you will always modify the weights for the egress interface. Example To set queue mode to WRR and WRR bandwidth for queues serving interface 1/3 Console(config)# queue mode wrr Console(config)#interface ethernet 1/3 Console(config-if)# queue bandwidth 1 1 1 2 2 2 2 15 Console(config-if)# exit Interoperability with OmniSwitch 6624/6648 7700/7800 8800 Usually, there is no such queue mode in these switches. The queues are always in a strict mode. The only modules that can be configured in a WRR mode are the High-Density modules GNI-U12/GNI-C12 on OmniSwitch 7700/7800 and GNI-U24/GNI-C24 on OmniSwitch 8800. The only location to configure a WRR in your network is on OmniStack 6300-34 or High-Density modules. 3. Priority CoS (Class of service) The switch has 8 priority queues per egress port. The switch uses CoS to determine the priority of a packet. Each CoS value is mapped to a priority queue using the CoS/Queue table. The default table is: Priority Queue CoS value 2 0 0 1 1 2 3 3 4 4 5 5 6 6 7 7 CoS means a lot of things. CoS is an input value between 0 and 7 the switch uses to determine the priority queue. The key is to know where that CoS came from. The switch has several ways to interpret a CoS value: Using the 802.1p from tagged packet, default mode Using the port default priority for untagged packets Using the IP precedence (TOS) from IP packets Using the IP DSCP (diffServ) from IP packets Using an ACL to map specific packets to a CoS Interoperability with OmniSwitch 6624/6648 7700/7800 8800 OmniSwitch 7700/7800 and 8800 only support 4 queues per egress port. OmniSwitch 6624/6648 supports 8 queues per egress port. 3.1 802.1p Priority (tagged packets) By default, the switch uses the 802.1p value seen in the incoming packets to determine the CoS. In that mode, CoS and 802.1p are the same. The priority queues are chosen using the table: Priority Queue 802.1p (CoS) 2 0 0 1 1 2 3 3 4 4 5 5 6 6 7 7 All incoming-tagged packets are prioritized based on the 802.1p value they carry on their VLAN header. The outgoing packets still carry the original 802.1p value. Packets are never modified. Interoperability with OmniSwitch 6624/6648 7700/7800 8800 These switches do the same but they use a different table. For instance OmniSwitch 7700/7800 and OmniSwitch 8800 map the 802.1p values to only 4 priority queues. Priority Queue 802.1p 0 0 0 1 1 2 1 3 2 4 2 5 3 6 3 7 Packets with 802.1p 0 get the lowest priority whereas they get priority 2 on OmniStack 6300-24 3.2 Default priority / Default 802.1p (untagged packets) By default, the switch uses the 802.1p value seen in the incoming packets to determine the CoS. For incoming untagged packets, the switch ha ...