Channel-Group


There are several ways to negotiate the link.
The Port Aggregation Protocol (PAgP) is a Cisco-proprietary protocol that can be run only on Cisco switches and on those switches licensed by vendors to support PAgP. PAgP facilitates the automatic creation of EtherChannels by exchanging PAgP packets between Ethernet ports. You can use PAgP only in single-switch EtherChannel configurations; PAgP cannot be enabled on cross-stack EtherChannels.

Table 30-1 EtherChannel PAgP Modes

auto

Places a port into a passive negotiating state, in which the port responds to PAgP packets it receives but does not start PAgP packet negotiation. This setting minimizes the transmission of PAgP packets.

desirable

Places a port into an active negotiating state, in which the port starts negotiations with other ports by sending PAgP packets.

on

Forces a port to channel without PAgP (or LACP). In the on mode, a usable EtherChannel exists only when a port group in the on mode is connected to another port group in the on mode. This is the only setting that is supported when the EtherChannel members are from different switches in the switch stack (cross-stack EtherChannel).

The LACP is defined in IEEE 802.3ad and enables Cisco switches to manage Ethernet channels between switches that conform to the IEEE 802.3ad protocol. LACP facilitates the automatic creation of EtherChannels by exchanging LACP packets between Ethernet ports. You can use LACP only in single-switch EtherChannel configurations; LACP cannot be enabled on cross-stack EtherChannels
Table 30-2 EtherChannel LACP Modes

active

Places a port into an active negotiating state in which the port starts negotiations with other ports by sending LACP packets.

passive

Places a port into a passive negotiating state in which the port responds to LACP packets that it receives, but does not start LACP packet negotiation. This setting minimizes the transmission of LACP packets.

on

Forces a port to channel without PAgP or LACP. With the on mode, a usable EtherChannel exists only when a port group in the on mode is connected to another port group in the on mode. This is the only setting that is supported when the EtherChannel members are from different switches in the switch stack (cross-stack EtherChannel).

To use loadbalincing between the switches :
3560_Remote(config)#port-channel load-balance src-dst-ip

Some show commands :
S3750#sho etherchannel load-balance
EtherChannel Load-Balancing Configuration:
src-dst-ip

S3750#show etherchannel ?
Channel group number
detail Detail information
load-balance Load-balance/frame-distribution scheme among ports in
port-channel
port Port information
port-channel Port-channel information
protocol protocol enabled
summary One-line summary per channel-group
| Output modifiers

About Joost van der Made

Me

One response to “Channel-Group”

  1. andy says :

    Hi,

    I have very limited knowledge on wireless and I have configured one WLC 4402 yesterday. The WLC will be connecting to a 3750 stacking switch and I am thinking about enabling LAG on WLC and connect it to two physical switch ( one logical switch ) for redundancy. The I saw the following statement on Cisco WLC configuration guide “When configuring bundled ports on the controller, you may want to consider terminating on two different modules within a modular switch such as the Catalyst 6500; however, Cisco does not recommend connecting the LAG ports of a 5500 or 4400 series controller to multiple Catalyst 6500 or 3750G switches.” I am wondering if you have done this before and what’s the reason it’s not recommended? BTW, I read your how to pass CCIEW and it
    s very helpful. I am currently preparing CCIE R&S and expect to take the lab around Nov this year. Thank you !!!

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