Re: EtherChannel mode ON ? Any catch?

Thanks everyone for great inputs.

On Thursday, October 7, 2010, Ivan Walker <ivan_at_itpro.co.nz> wrote:
> I would also add that using LACP can be useful when end-to-end connectivity is not reflected in the link status of the interface - for example - using media converters or perhaps a QinQ service.
>
> LACP control packets are sent at 30 second intervals after bundling and give and end to end check. Using "lacp rate fast" this is reduced to 1 second (much more useful) Note that the dead time is 3x the hello time... Unfortunately last time I looked I think only the high end switches supported the fast timers :-(
>
> Ivan
>
> On 6/Oct/2010 11:37 p.m., Marko Milivojevic wrote:
>
> 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
>
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>
> 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.
>
>
> Blogs and organic groups at http://www.ccie.net
>
> __________________________________________

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