DCB Configuration Guide

after network convergence in a data center, three types of traffic exist lan traffic, san traffic, and ipc traffic, each with distinct qos requirements san traffic san traffic is highly sensitive to packet loss and requires in order delivery of packets during transmission lan traffic lan traffic allows packet loss and only requires best effort (be) service from the network ipc traffic ipc traffic (used for server to server communication) demands low latency data center bridging (dcb) is a set of ieee 802 1 bridging enhancements that meet these qos requirements by creating a lossless ethernet infrastructure for converged data center networks dcb fundamentals dcb fundamentals dcb features primarily include pfc, ets, and dcbx pfc pfc pfc (priority based flow control) consists of priority based flow control and pfcwd (pfc watchdog) for details, please refer to https //docs asteraix com/aidc/qos configuration guide#8o4di in qos configuration guide ets ets in a converged data center network, the coexistence of lan, san, and ipc traffic imposes stringent qos demands for example san traffic san traffic is sensitive to packet loss and requires ordered delivery ipc traffic ipc traffic demands ultra low latency for server communication lan traffic lan traffic only requires best effort service, where packet loss and reordering can be handled by end hosts, minimizing network intervention traditional qos mechanisms cannot meet these requirements enhanced transmission selection (ets) addresses this by enabling flexible traffic scheduling for converged networks ets defines a priority based processing model and bandwidth allocation model for endpoints and bridges in dcb environments this allows differentiated services and bandwidth allocation for different traffic types for scheduling details, please refer to https //docs asteraix com/aidc/qos configuration guide#6wch for priority mapping details, please refer to https //docs asteraix com/aidc/qos configuration guide#brvly dcbx dcbx data center bridging exchange protocol (dcbx) is a component of dcb it operates in dcb environments to enable devices on both ends of a link to discover and exchange dcb configuration parameters, significantly reducing administrative overhead key dcbx functions discover the dcb configuration of peer devices detect dcb configuration errors on peer devices configure dcb parameters on peer devices dcbx exchangeable parameters ets scheduling and priority information pfc configurations dcbx uses lldp (link layer discovery protocol) to exchange information dcb configuration parameters are encapsulated into tlvs (type length value fields) within lldp frames, enabling automatic dcb parameter negotiation between devices configure dcb configure dcb configure pfc configure pfc please refer to https //docs asteraix com/aidc/qos configuration guide#ycme5 configure pfcwd configure pfcwd please refer to https //docs asteraix com/aidc/qos configuration guide#zcrdq configure ets configure ets please refer to https //docs asteraix com/aidc/qos configuration guide# zwk6 and https //docs asteraix com/aidc/qos configuration guide#1tycn configure dcbx configure dcbx notes before enabling dcbx, ensure lldp is enabled interfaces with ets configuration synchronization enabled must retain default configurations for scheduling and priority mapping table 1 configure dcbx table 1 configure dcbx purpose commands description enter global configuration view configure terminal enter interface configuration view interface ethernet interface name enable dcbx lldp dcbx enable enable pfc configuration synchronization lldp dcbx pfc willing enable ets configuration synchronization lldp dcbx ets willing display and maintenance display and maintenance pfc information pfc information please refer to https //docs asteraix com/aidc/qos configuration guide#hxlsk pfcwd information pfcwd information please refer to https //docs asteraix com/aidc/qos configuration guide#2fcu5 ets information ets information please refer to https //docs asteraix com/aidc/qos configuration guide#clvff and https //docs asteraix com/aidc/qos configuration guide#9m3qj dcbx information dcbx information table 2 dcbx information table 2 dcbx information purpose commands description display dcbx configuration and status show lldp dcbx typical configuration example typical configuration example networking requirement in the data center network, two data center switches (switch a and switch b) are interconnected, under which servers are running storage traffic, ipc traffic (802 1p priority 7) and general data traffic; it is necessary to achieve no packet loss for storage traffic, low latency for icp, and best effort forwarding for general traffic topology configuration roadmap configure dcbx (data center bridging exchange protocol) on switch a to automatically negotiate dcb capabilities with peer devices at both ends of the link activate priority based flow control (pfc) on switch a to ensure lossless transmission for storage traffic (e g , san traffic) set up enhanced transmission selection (ets) with priority mapping and scheduling policies ensure low latency for ipc traffic and guaranteed bandwidth allocation for storage traffic procedure \#configure dcbx switch a sonic# configure sonic(config)# interface ethernet 0/0 sonic(config if 0/0)# lldp dcbx enable switch b sonic# configure sonic(config)# interface ethernet 0/0 sonic(config if 0/0)# lldp dcbx enable sonic(config if 0/0)# lldp dcbx ets willing sonic(config if 0/0)# lldp dcbx pfc willing \#configure pfc enable the pfc function for priority 3 queues by default, the global pfc function is enabled, and the priority 3 queue has already enabled the pfc function, so this configuration step is omitted sonic# configure sonic(config)# priority flow control enable3 \#configure ets create priority mapping sonic# configure sonic(config)# diffserv map type 8021p ets sonic(config diffservmap ets)# 8021p 7 cos 7 create policy map and bind diffserv map sonic# configure sonic(config)# policy map ets sonic(config pmap ets)# set cos 8021p diffserv ets configure queue scheduler sonic(config pmap ets)# queue scheduler queue limit percent 40 queue 0 sonic(config pmap ets)# queue scheduler priority queue 7 bind policy map to interface sonic# configure sonic(config)# interface ethernet 0/0 sonic(config if 0/0)# service policy ets verify the configuration \#pfc configure sonic# show interface priority flow control interface lossless priorities \ 0/0 3,4 0/1 3,4 0/2 3,4 0/3 3,4 0/4 3,4 0/5 3,4 0/6 3,4 0/7 3,4 0/8 3,4 0/12 3,4 0/13 3,4 0/14 3,4 0/15 3,4 0/16 3,4 0/20 3,4 0/24 3,4 0/28 3,4 0/32 3,4 0/33 3,4 0/34 3,4 0/35 3,4 0/36 3,4 0/37 3,4 \#policy map configure sonic# show policy map ets ！ policy map ets queue scheduler priority queue 7 queue scheduler queue limit percent 40 queue 0 set cos dscp diffserv ets \#diffserv map configure sonic# show diffserv map type 8021p ets diffserv map ets type 8021p from 7 to 7 \#dcbx configure and status sonic# show lldp dcbx interface ets willing pfc willing ets accepted pfc accepted \ 0/0 true true false false