6509 switch ethernet blade port population vs efficiency

Unanswered Question
Dec 9th, 2009

Is there a general rule of thumb on how a switch ethernet blade should be populated in relation to getting the best performance per asic/port combination?


For example:


If I have a four 10/100 ethernet blades on a 6509 and there are 12 ports per asic on each blade, 140 users, 20 servers and 32 printers.


Would it make any difference how I populate the blades in how efficient the usage/utilization of each port/asic/blade is?


Does it matter if I populate three blades with all workstations and one blade with printers and servers?


Or should there be a printer (low utilization) in each asic/port group?


Should there be an attempt to try and balance the load on each asic/port group?


Are there any guidlines for this type of application?

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Giuseppe Larosa Wed, 12/09/2009 - 22:07

Hello Richard,

I guess you have some type of 6148 or 6248 linecards


datasheet link is here:


http://www.cisco.com/en/US/prod/collateral/switches/ps5718/ps708/product_data_sheet0900aecd8017376e.html



From the point of view of performance you should spread the high traffic volume devices (the servers) one or two for port groups as evenly as possible.


Actually each group of ports that share the same resources (ASIC) are constrained to the performance of them (the ASIC).


if you can check ports to ASIC mapping with this command explained by Edison in another thread:


sh interfaces capabilities module x


this is an example from a 6748 linecard:


sh interfaces capabilities module 2
GigabitEthernet2/1
  Model:                 WS-X6748-GE-TX
  Type:                  10/100/1000BaseT
  Speed:                 10,100,1000,auto
  Duplex:                half,full
  Trunk encap. type:     802.1Q,ISL
  Trunk mode:            on,off,desirable,nonegotiate
  Channel:               yes
  Broadcast suppression: percentage(0-100)
  Flowcontrol:           rx-(off,on,desired),tx-(off,on,desired)
  Membership:            static
  Fast Start:            yes
  QOS scheduling:        rx-(2q8t), tx-(1p3q8t)
  CoS rewrite:           yes
  ToS rewrite:           yes
  Inline power:          no
  SPAN:                  source/destination
  UDLD                   yes
  Link Debounce:         yes
  Link Debounce Time:    no
  Ports on ASIC:         1-12
  Port-Security:         yes


Also on last generation there is one asic every 12 ports but performances are better



putting all the servers together would be wise if you had one WS-6748 linecard in that case I would so in this way (caution: it requires sup720 as explained in the datasheet)


Hope to help

Giuseppe

Jon Marshall Thu, 12/10/2009 - 03:31

wilson_1234 wrote:


Is there a general rule of thumb on how a switch ethernet blade should be populated in relation to getting the best performance per asic/port combination?


For example:


If I have a four 10/100 ethernet blades on a 6509 and there are 12 ports per asic on each blade, 140 users, 20 servers and 32 printers.


Would it make any difference how I populate the blades in how efficient the usage/utilization of each port/asic/blade is?


Does it matter if I populate three blades with all workstations and one blade with printers and servers?


Or should there be a printer (low utilization) in each asic/port group?


Should there be an attempt to try and balance the load on each asic/port group?


Are there any guidlines for this type of application?


Richard


Firstly, performance aside, it is not a good idea to populate one module with all the servers/printers because if that one module fails then so on effect does your network. Your servers may be dual honed so that may not be so important but i would definitely spread the printers among the worksation modules just so in the event of a module failure there are at least some printers available.


How you populate the blade depends on how much throughput you need and how much throughput the blade provides eg.


WS-X6548-GE-TX with a Sup720 or Sup2 + SFM (Switch fabric Module) = 8Gbps connection to the switch fabric

WS-X6748-GE-TX  with a Sup720 = 40Gbps connection to the switch fabric


Each of the above blades has 48 10/100/1000 ethernet ports but they clearly have very different oversubscription rates ie. the 6548 will support 8 devices running at 1Gbps before becoming oversubscribed and the 6748 40 devices.


So it's more a question of the blade capability than the port groups although you should be aware of the port groups and try to spread the load across the ASICs.


Jon

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