Re: EtherChannel mode ON ? Any catch?

On an ideal world, On would be fine I guess.
But dynamic negotiation of the bundle allows for those oops, that would
render half (or 1/3) of your traffic being black holed, to be managed.
LACP can do sort of protection too AFAIK (i.e. have standby links).
-Carlos

Tech Guy @ 5/10/2010 20:35 -0300 dixit:
> 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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>

-- 
Carlos G Mendioroz  <tron_at_huapi.ba.ar>  LW7 EQI  Argentina
Blogs and organic groups at http://www.ccie.net