Go Premium for a chance to win a PS4. Enter to Win

x
?
Solved

Cisco 3500 etherchannel port groups

Posted on 2011-02-12
6
Medium Priority
?
1,151 Views
Last Modified: 2012-06-27
I have 3 Cisco 3500xl switches that I want to daisy chain together.  Switch A will connect to B, and B will connect to C.  

When configuring the port group, should I create 2 separate port groups?  For example if I have 'SwitchA' F0/1, F0/2, & 'SwitchB' F0/1 & F0/2 in 'port group 1', and SwitchB F0/3, F0/4 & SwitchC F0/3, & F0/4 in port group 2, is this the correct way to configure it?  

Should all ports be in one port group amongst all switches, or is the 'Port Group' number only locally significant?   I'm guessing on switch 2, there has to be 2 separate port groups, a different one going to each switch or you will get a switching loop.  
0
Comment
Question by:B1izzard
6 Comments
 

Assisted Solution

by:manni78
manni78 earned 600 total points
ID: 34881007
Yes you have create two difrrent channels for different switches connected to each other. Example Channel 1 for Switch A & B Port fa0/1-2; channel 2 for B & C Port fa0/3-4.
0
 

Author Comment

by:B1izzard
ID: 34881090
If you do not, does it cause a switching loop I'm assuming?
0
 
LVL 17

Accepted Solution

by:
Marius Gunnerud earned 1000 total points
ID: 34882136
Group numbers are local to the switch so you can have channel-group 1 with fa0/1 & fa 0/2 on one switch connecting to fa0/1 & fa0/2 in channel group 2 on another switch.  You can not have two channel groups of the same number on one switch.  All ports in a channel group must go to the same destination.

It will not create a loop but an inconsistancy will be created. When data exchang is initiated the switches elects a path/link for that traffic in the etherchannel for the duration. If a link that is going to a different switch is chosen the packets will never reach its destination.  There for in a non stack environment all channel groups must have links going to the same destination.

The way around this is to stack the switches at the other end of the link. Lets say that there are 3 switches that are stacked. Then one switch with channel group 1 can have 1 link going to each stacked switch within the same channel group as the stack is considered to be the same destination for the channel group.
0
How to Use the Help Bell

Need to boost the visibility of your question for solutions? Use the Experts Exchange Help Bell to confirm priority levels and contact subject-matter experts for question attention.  Check out this how-to article for more information.

 

Expert Comment

by:manni78
ID: 34882360
B1izzard, It will not create loop but you channel will not work.....
0
 
LVL 8

Assisted Solution

by:SeeMeShakinMyHead
SeeMeShakinMyHead earned 400 total points
ID: 34882546
If using VLANs other than just VLAN1, you will get VLAN mismatches as well.  For consistency, just name channel-group 1 on both ends for swA to swB and channel-group 2 for swB to swC.  Make sure encapsulation, vlans, and speed/duplex are the same on both ends.
0
 

Author Closing Comment

by:B1izzard
ID: 34883199
Great explanations.  Thanks.
0

Featured Post

Vote for the Most Valuable Expert

It’s time to recognize experts that go above and beyond with helpful solutions and engagement on site. Choose from the top experts in the Hall of Fame or on the right rail of your favorite topic page. Look for the blue “Nominate” button on their profile to vote.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

The worst thing when starting a new job is when the previous Network Administrator left behind no documentation. How do you get into the devices? If you've been in this situation or just accidently mistyped your password, this article will hopefully…
Arrow Electronics was searching for a KVM  (Keyboard/Video/Mouse) switch that could display on one single monitor the current status of all units being tested on the rack.
We’ve all felt that sense of false security before—locking down external access to a database or component and feeling like we’ve done all we need to do to secure company data. But that feeling is fleeting. Attacks these days can happen in many w…
Please read the paragraph below before following the instructions in the video — there are important caveats in the paragraph that I did not mention in the video. If your PaperPort 12 or PaperPort 14 is failing to start, or crashing, or hanging, …
Suggested Courses

885 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question