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New Member

2950-Etherchannel

Hi,

We are using 2950 switch, which is connected to another switch and etherchannel “Fast Ethernet” between the two switches. But when we check speed it is shows 100 instead of 200. I’m right to think that EtherChannel just balances the traffic load across the links, but does not aggregate Ports speed. ???

Regards

11 REPLIES

Re: 2950-Etherchannel

Yes, you are right.

Etherchannels use an algorithm based on source or dest mac's to balance traffic. All traffic for a specific session always takes the same path. So this path will never have more than 100Mb available.

Effectively this is a form of load-balancing that relies on the requirement that there are multiple sources on at least one side, i.e. one server vs many clients. Between two switches you will almost always have multiple sources on both sides.

Regards,

Leo

Cisco Employee

Re: 2950-Etherchannel

Here is link that will explain more

http://www.cisco.com/warp/customer/473/4.html

New Member

Re: 2950-Etherchannel

Hi,

Could someone explain difference in using Layer-3 etherchannel and Layer-2 etherchannel???.... does it depent connection to the switch i.e router or L2 device.

Thanks

Cisco Employee

Re: 2950-Etherchannel

If the members of your etherchannel are in a VLAN(or a trunk), then it's a layer 2 etherchannel. If the ports have an IP address under the port-channel, then it's a layer 3 etherchannel

Cisco Employee

Re: 2950-Etherchannel

it depends whether the ports in channel are l2 or l3 ports. It connect to another switch back to back like core switches that can do l2 port channel or l3 channel can connect to the routes and l2 channel can connect to pure l2 devices, like 2950 and 2948g switches as l2 channel n 3550 or 4006-sup3 back to back or to any layer 3 devices like router as l3 channel

hope this link helps you more

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/12_1e/swconfig/channel.htm

Cisco Employee

Re: 2950-Etherchannel

Hi,

I have configured Etherchannel between a 2950 and 3500XL.

I am able to check the configuration in the 3500XL:

Under the interface we can see:

interface FastEthernet0/15

port group 1

and

3500XL#sh etherchannel 1 brief

Group state = L2

Ports: 2 Maxports = 8

It seems that it is not possible with 2950.

None in the interface and none in the sh command.

How can I check that it is correctly up and running?

Any help appreciated

Matteo

Cisco Employee

Re: 2950-Etherchannel

New Member

Re: 2950-Etherchannel

Hi,

did You have success with this etherchannel? I did not. Etherchannel between two 2950 works properly, but between 2950 and 2900 rather as broadcast storm generator.

Could you tell me, what I have probably overseen?

Tomas

Cisco Employee

Re: 2950-Etherchannel

what software versions are you using-

New Member

Re: 2950-Etherchannel

12.0(5)WC5 on 2924M-XL-EN and

12.1(12c)EA1 on 2950T-24 .

Thanks for your prompt reaction.

Tomas

New Member

Re: 2950-Etherchannel

Hi, I have solved this connection on myself at last. (If all failed, read

the guide...) Critical is to choose the appropriate option "mode on"

by channel-group command at 2950 site.

I am sorry for bothering anybody.

Tomas

cs-t1#show ver

Cisco Internetwork Operating System Software

IOS (tm) C2900xl Software (C2900xl-C3H2S-M), Version 12.0(5)WC5,...

cs-t1#conf term

Enter configuration commands, one per line. End with CNTL/Z.

cs-t1(config)#int fa0/12

cs-t1(config-if)#port group 1

cs-t1(config-if)#exit

cs-t1(config)#int fa0/13

cs-t1(config-if)#port group 1

cs-t1(config-if)#exit

cs-t1(config)#int fa0/14

cs-t1(config-if)#port group 1

cs-t1(config-if)#end

cs-t1#show port group

Group Interface Transmit Distribution

----- --------------------- ---------------------

1 FastEthernet0/12 source address

1 FastEthernet0/13 source address

1 FastEthernet0/14 source address

cs-t4#show ver

Cisco Internetwork Operating System Software

IOS (tm) C2950 Software (C2950-I6Q4L2-M), Version 12.1(12c)EA1,...

cs-t4#conf term

Enter configuration commands, one per line. End with CNTL/Z.

cs-t4(config)#int fa0/12

cs-t4(config-if)#channel-group 1 mode on

Creating a port-channel interface Port-channel 1

cs-t4(config-if)#exit

cs-t4(config)#int fa0/13

cs-t4(config-if)#channel-group 1 mode on

cs-t4(config-if)#exit

cs-t4(config)#int fa0/14

cs-t4(config-if)#channel-group 1 mode on

cs-t4(config-if)#end

cs-t4#show eth summ

Flags: D - down P - in port-channel

I - stand-alone s - suspended

H - Hot-standby (LACP only)

R - Layer3 S - Layer2

u - unsuitable for bundling

U - in use f - failed to allocate aggregator

d - default port

Number of channel-groups in use: 1

Number of aggregators: 1

Group Port-channel Protocol Ports

------+-------------+-----------+-------------------------------

1 Po1(SU) - Fa0/12(Pd) Fa0/13(P) Fa0/14(P)

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