Re: EtherChannel mode ON ? Any catch?

I have been an advocate of ON due to the fact that we are not depending on
any negotiation for setting up the ether-channel.
When submitted a large enterprise network design to Cisco, they recommended
to use PAgP when connecting two Cisco switches and use LACP when connecting
from Cisco to third party switch.
Some of the etherchannel requirements do not support all forms of
negotiations; following are the couple that comes to my mind.
WLCs do not support PACP for LAG - they need to be PAgP
VSLs for VSSs do not support neither - they need to be ON
PAgP is not supported on Cross Stack 3750 stack members - LACP is the only
supported option

So, the bets answer is IT DEPENDS when choosing the etherchannel mode.

my 2 cents,
-Shine

--------------------------------------------------
From: "Marko Milivojevic" <markom_at_ipexpert.com>
Sent: Wednesday, October 06, 2010 6:37 PM
To: "Tech Guy" <autechguy_at_gmail.com>
Cc: "CCIE Lab" <ccielab_at_groupstudy.com>
Subject: Re: EtherChannel mode ON ? Any catch?

> With "on", you're running the risk of bridging loops if other end is
> misconfigured. If that risk is acceptable and ~2s of initial negotiation
> delay of LACP/PAgP isn't, use it.
>
> I would suggest you use LACP.
>
> --
> Marko Milivojevic - CCIE #18427
> Senior Technical Instructor - IPexpert
>
> Free CCIE Training: http://bit.ly/vLecture
>
> Mailto: markom_at_ipexpert.com
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> Community: http://www.ipexpert.com/communities
>
> :: Sent from my phone. Apologies for errors and brevity. ::
>
> On Oct 5, 2010, at 19:35, Tech Guy <autechguy_at_gmail.com> wrote:
>
>> Hi GS,
>>
>>
>> LACP takes some time to negotiate, while mode ON does not require it,
>> and hence gives a better convergence time. I am not sure if there's
>> any issue with using EtherChannel mode ON, instead of LACP (apart from
>> user-misconfig issues). This is not clear in the DOC CD configuration
>> guide.
>>
>> More specifically, if we have two Cisco switches, and need to
>> configure ether-channel between them, would you recommend mode ON or
>> LACP (open standard). E.g. issue with mode ON such as one link is
>> recognised as UP at one end, but as DOWN by the switch at the other
>> end.
>>
>>
>> Appreciate your feedbacks.
>>
>>
>>
>> http://www.cisco.com/en/US/docs/switches/lan/catalyst3560/software/release/12.2_44_se/configuration/guide/swethchl.html#wp1275503
>>
>>
>>
>>
>>
>>
>>
>> Understanding EtherChannels
>> These sections describe how EtherChannels work:
>>
>> EtherChannel Overview
>>
>> Port-Channel Interfaces
>>
>> Port Aggregation Protocol
>>
>> Link Aggregation Control Protocol
>>
>> EtherChannel On Mode
>>
>> Load Balancing and Forwarding Methods
>>
>> EtherChannel Overview
>> An EtherChannel consists of individual Fast Ethernet or Gigabit
>> Ethernet links bundled into a single logical link as shown in Figure
>> 34-1.
>>
>> Figure 34-1 Typical EtherChannel Configuration
>>
>>
>>
>> The EtherChannel provides full-duplex bandwidth up to 800 Mb/s (Fast
>> EtherChannel) or 8 Gb/s (Gigabit EtherChannel) between your switch and
>> another switch or host.
>>
>> Each EtherChannel can consist of up to eight compatibly configured
>> Ethernet ports. All ports in each EtherChannel must be configured as
>> either Layer 2 or Layer 3 ports. The number of EtherChannels is
>> limited to 48. For more information, see the "EtherChannel
>> Configuration Guidelines" section. The EtherChannel Layer 3 ports are
>> made up of routed ports. Routed ports are physical ports configured to
>> be in Layer 3 mode by using the no switchport interface configuration
>> command. For more information, see the Chapter 10, "Configuring
>> Interface Characteristics."
>>
>> You can configure an EtherChannel in one of these modes: Port
>> Aggregation Protocol (PAgP), Link Aggregation Control Protocol (LACP),
>> or On. Configure both ends of the EtherChannel in the same mode:
>>
>> When you configure one end of an EtherChannel in either PAgP or LACP
>> mode, the system negotiates with the other end of the channel to
>> determine which ports should become active. Incompatible ports are
>> suspended. Beginning with Cisco IOS Release 12.2(35)SE, instead of a
>> suspended state, the local port is put into an independent state and
>> continues to carry data traffic as would any other single link. The
>> port configuration does not change, but the port does not participate
>> in the EtherChannel.
>>
>> When you configure an EtherChannel in the on mode, no negotiations
>> take place. The switch forces all compatible ports to become active in
>> the EtherChannel. The other end of the channel (on the other switch)
>> must also be configured in the on mode; otherwise, packet loss can
>> occur.
>>
>> If a link within an EtherChannel fails, traffic previously carried
>> over that failed link moves to the remaining links within the
>> EtherChannel. If traps are enabled on the switch, a trap is sent for a
>> failure that identifies the switch, the EtherChannel, and the failed
>> link. Inbound broadcast and multicast packets on one link in an
>> EtherChannel are blocked from returning on any other link of the
>> EtherChannel.
>>
>>
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>>
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>
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Received on Wed Oct 06 2010 - 21:36:09 ART