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 \<font color="#1d05a2">san traffic\</font> is highly sensitive to packet loss and requires in order delivery of packets during transmission \<font color="#1d05a2">lan traffic\</font> allows packet loss and only requires best effort (be) service from the network \<font color="#1d05a2">ipc traffic\</font> (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 \<font color="#1d50a2">dcb fundamentals\</font> dcb features primarily include pfc, ets, and dcbx \<font color="#1d50a2">pfc\</font> pfc (priority based flow control) consists of priority based flow control and pfcwd (pfc watchdog) for details, please refer to pfc https //docs asteraix com/aidc/qos configuration guide#8o4di in qos configuration guide \<font color="#1d50a2">ets\</font> in a converged data center network, the coexistence of lan, san, and ipc traffic imposes stringent qos demands for example \<font color="#1d05a2">san traffic\</font> is sensitive to packet loss and requires ordered delivery \<font color="#1d05a2">ipc traffic\</font> demands ultra low latency for server communication \<font color="#1d05a2">lan traffic\</font> 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 congestion management https //docs asteraix com/aidc/qos configuration guide#6wch for priority mapping details, please refer to queue and priority mapping https //docs asteraix com/aidc/qos configuration guide#brvly \<font color="#1d50a2">dcbx\</font> 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 \<font color="#1d50a2">configure dcb\</font> \<font color="#1d50a2">configure pfc\</font> please refer to configure pfc https //docs asteraix com/aidc/qos configuration guide#ycme5 \<font color="#1d50a2">configure pfcwd\</font> please refer to configure pfcwd https //docs asteraix com/aidc/qos configuration guide#zcrdq \<font color="#1d50a2">configure ets\</font> please refer to configure qos priority mapping https //docs asteraix com/aidc/qos configuration guide# zwk6 and configure qos schedule policy https //docs asteraix com/aidc/qos configuration guide#1tycn \<font color="#1d50a2">configure dcbx\</font> notes before enabling dcbx, ensure lldp is enabled interfaces with ets configuration synchronization enabled must retain default configurations for scheduling and priority mapping \<font color="#1d05a2">table 1 configure dcbx\</font> 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 \<font color="#1d50a2">display and maintenance\</font> \<font color="#1d50a2">pfc information\</font> please refer to pfc information https //docs asteraix com/aidc/qos configuration guide#hxlsk \<font color="#1d50a2">pfcwd information\</font> please refer to pfcwd information https //docs asteraix com/aidc/qos configuration guide#2fcu5 \<font color="#1d50a2">ets information\</font> please refer to diffserv map information https //docs asteraix com/aidc/qos configuration guide#clvff and policy map information https //docs asteraix com/aidc/qos configuration guide#9m3qj \<font color="#1d50a2">dcbx information\</font> \<font color="#1d05a2">table 2 dcbx information\</font> purpose commands description display dcbx configuration and status show lldp dcbx \<font color="#1d50a2">typical configuration example\</font> 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