思科CMTS-负载均衡课件

Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,#,13-12-18,CMTS Load Balance Overview,By,Zhimin,Zhang,How LB usually,work,Each,LBG,contains,some,DS/US,channel.,When,modem,is,registered,it,will,be,assigned,to,a,LBG,(,except,legacy,LBG.),CMTS,check,the,balance,status,periodically,if,not,balanced,move,some,modem,to,lower,load,channel.,How to measure balance status,Modem,count,Whether,modem,number,is,balanced,across,channels.,Utilization,Whether,traffic,load,is,balanced.,Service,flow(not support anymore),Whether,service,flow,number,is,balanced.,The,load,is,counted,base,on,channel,not,only,within,LBG.,“show,cable,load,load”,Modem move strategy,(When,and,how,many,times,to,move),Static LB,Move,modem,once,after,registered,Dynamic,LB,Move,modem,whenever,not,balanced.,Passive,LB,CMTS,ignore,the,register,for,modem,on,overload,channel,How to move modem,(message,send,to,modem),DCC,Move,primary,DS,DBC,Move,both,primary,and,bonding,group.,UCC,Move,upstream,only,Init,tech,0-4,configurable.,LB Types,Legacy Load Balancing,(Not supported in new release),Cant differentiate individual modem,Docsis,Load Balancing,D2.0,GLBG,(D2.0 modems),D3.0,GLBG,(D3.0 modems),RLBG(both 2.0/3.0),Modem,will,be,assigned,to,a,load,balance,group,to,take,effect.,“show,cable,load-balance”,How to create LBG,2.0 GLBG/RLBG use the same command,but RLBG has a restrict keyword,cable load-balance docsis-group 1,restricted,downstream,Modular-Cable 7/1/0 rf-channel 0-7,upstream,Cable7/1/0 0-,3,3,.0,GLBG,are,created,automatically,when,FN,is,created.,Cant,be,created,by,CLI,but,parameter,can,be,changed.,Legacy Load Balancing,Cisco private solution.,Not,process,each,individual,modem,after,registered.,No,LBG,assignment.,Docsis LB,Assignment,RLBG,has,the,highest,priority,If,a,modem,does,not,match,the,RLBG,then,it,will,be,assigned,to,GLBG,base,on,DOCSIS,version,and,channel,set.,2.0,modem,is,assigned,to,2.0,GLBG.,3,.0,modem,is,assigned,to,3.0,GLBG.,RLBG,can,match,tagging,oui,docsis-version,service,type,cli,GLBG,are,assigned,by,channel,set.,To,save,the,system,resource,Since,there,may,be,tens,of,thousands,of,modems.,LB,will,not,move,modem,in,real,time,it,will,check,the,balance,status,after,every,specific,interval,.,Default,30s.,“interval”.,To reduce ping-pong effect(flap),In,a,platform,with,unstable,modems,offline/online,cmts,will,always,found,its,un-balanced,and,try,to,move,modem.,Traffic,statistics,has,a,delay,so,CMTS,may,move,to,many,modems,to,another,channel,and,have,to,move,it,back,in,next,interval.,Threshold,is,used,to,accept,somewhat,un-balance.,So,that,it,will,not,waste,unnecessary,resource.,“threshold”,Treat voice/video different,By,default,modem,that,has,special,service,will,not,be,moved,by,LB.,But,this,can,be,changed,by,“policy”,command.,This is to ensure the service quality.,“policy”,We dont want a specific modem to,be moved,Exclude,command,“docsis,-policy”,could,be,used,to,disable,a,modem,being,moved,permanently,or,for,some,period.,“docsis-policy”,Continue,For,utilization,based,move,a,modem,that,with,high,traffic,will,be,more,efficient,because,less,modem,needs,to,be,moved.,But,if,the,traffic,is,very,high,such,as,75%,of,a,channel,then,better,not,to,move,it,because,it,may,make,other,channel,overload,as,well.,“,disable-throughput-lowerbound,”,to,define,what,is,high,load,modem,.,Upperbound,not,support,yet.,We may want some modems moved first,Some,modem,may,have,some,important,service,so,if,possible,move,other,modems,first.,LB,priority,in,modem,config,file.,Dynamic D3.0 LB,Currently,support,static/dynamic,LB,for,NB,modems.,Currently,support,static,LB,for,WB/UB,modems.,Now,we,are,trying,to,support,dynamic,LB,for,WB/UB,modems.,A lot of exception for LB,Case 1：,Channel,-,1 has 15%traffic,channel,-,2,has,1,percent,threshold,is,1,%.,Modem,will,be,moved,from,channel-1,to,channel-2.,But,since,channel,-,1,usage,is,also,very,low,its,not,needed,to,move,modem,at,all.,“min,-threshold”,is,used,to,avoid,unnecessary,modem,move.,