Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Community Member

2821 - Etherchannel

I am having issues with getting an etherchannel between a 2821 (on-board giga ports) and 3750. I have followed the config shown in the Cisco docs but can not ping the devices, and when I do a Show etherchannel command on the 2821 no ports are shown as being members

13 REPLIES

Re: 2821 - Etherchannel

Nick,

As far as I know is that Etherchannel doesn't support on the built-in ethernet interface. You may try to use Ethernet switch module to accomplish this.

HTH,

Toshi

Hall of Fame Super Gold

Re: 2821 - Etherchannel

Beside working or not, what exactly ether channel with gigabit buys you on a 2821 ?

A 2821 is unable to handle one wire speed gigabit, not to mention multiple ones.

And link redundancy on LAN links is never a real issue.

Super Bronze

Re: 2821 - Etherchannel

Hall of Fame Super Gold

Re: 2821 - Etherchannel

Doh, it agrees with what I was saying before...

Cfr second paragraph of "Applications".

Gotta love that "performance is at a premium" phrasing.

Super Bronze

Re: 2821 - Etherchannel

"Doh, it agrees with what I was saying before... "

Paolo, actually, according to our timestamps on our posts, it's what you were saying after. ;)

However, you're quite right, not a useful technique for gig Ethernet bandwidth on a 2821.

On redundancy, also agree there are other ways to address this, such as your mention of BVI and STP in your later post. However, ISR Etherchannel can also provide link/port redundancy, and although it increases device configuration complexity, can simplify the L2 or L3 topology in some situations, e.g. those dealing with a switch stack or different line cards on a chassis switch.

Community Member

Re: 2821 - Etherchannel

This is the example that I am trying to setup. Ian trying to use this design to provide some redundancy from switch failure.

Hall of Fame Super Gold

Re: 2821 - Etherchannel

You do not gain any redundancy from switch failure with etherchannel, because all links must go to the same switch.

If you are really worried about switch failure (and you should not not be), use a BVI config with links going to different switches. Note that will block one link due to STP.

Re: 2821 - Etherchannel

Joseph,

Thanks for pointing the document. I just read it. The first release of IOS that supports embedded interface to do Layer3 Etherchannel is 12.4(17.6).

As I mentioned,there are a lot of network modules can support this feature. Yes,document says that as well.

I used to test this once. It did't work. I did search from http://www.cisco.com/go/fn with an "etherchannel" keyword. Haven't seen ISR showing up there. I give you 5P! anyway (grin)

Nick, Please let us know how things work out.

Paolo, BVI is a good idea as well. STP will come into play. No more load-balancing. 5P! for sure

Toshi

Super Bronze

Re: 2821 - Etherchannel

Toshi,

BTW, I have been able to get it to work between 2811 and 3750 dual stack.

Re: 2821 - Etherchannel

Joseph,

Many thanks, I will lab it up tomorrow. Please let me know which ios version you did test.

Toshi

Super Bronze

Re: 2821 - Etherchannel

Toshi, not certain, it was some time back. I think version 12.4(18) or 12.4(19). Whatever was highest available with 12.4 at the time.

Community Member

Re: 2821 - Etherchannel

I am using the cross-stack on the 2 3750.

Community Member

Re: 2821 - Etherchannel

Keep in mind w/ distributed either-channel on 3750's you can only do static or LACP; PAgP isn't supported.

687
Views
10
Helpful
13
Replies
CreatePlease to create content