Cisco 3750 etherchannel clarification

[hussainirfan]

hi,

we have one cisco 3750 switch. As per  the datasheet it can support up to 8 Gbps etherchcannel gigabit aggregation bandwith

can we divide this total etherchannel bandwith into  groups by connecting two or more blade enclosures to one 3750 switch and configure etherchannel on all of them?

appreciate your help,

[Peter Paluch]

Hello Irfan,

Personally, I understand the datasheet differently: in my opinion, it says that a single EtherChannel can go up to 8 Gbps as each EtherChannel bundle can contain up to 8 active links, thus 8x1Gbps = 8Gbps. But you can create several independent EtherChannel bundles on the 3750, each being able to carry up to 8Gbps on its own, without sharing its bandwidth with other existing EtherChannels (of course until the switching fabric is oversubscribed - I do not know the total capacity of the 3750 backplane).

Best regards,

Peter

[hussainirfan]

thanks peter.Im not sure that i got you right.

you mean to say that we can create multiple ertherchannel group using one single switch to connect two or more blade/servers , each of these etherchannel group will be limited by 8 gbps bandwith?

any document from cisco for support?

thanks

[Peter Paluch · Accepted solution]

Hello,

Allow me to state my point once more: You can create several EtherChannel groups on a single 3750, connected to different blade switches. Each one of these EtherChannel groups can achieve up to 8Gbps of aggregated bandwidth, limited by the number and speed of active links in the group. The limit of 8Gbps relates always only to an individual EtherChannel group, not to all EtherChannel groups simultaneously.

The IOS Configuration Guide for 3750 available at:

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_55_se/configuration/guide/swethchl.html

suggests that you can create up to 48 EtherChannels on a single 3750 or on a switch stack. It mentions that the limit on an EtherChannel (individual group) is 800 Mbps with FastEthernet interfaces and 8 Gbps with GigabitEthernet interfaces.

Best regards,

Peter