Load sharing modes and switching modes

badalam_nt · ‎02-22-2009

I'm a bit confused about the load sharing modes and switching modes interaction.

My understanding is the following, please correct me if I'm wrong:

1) load sharing can be done in 3 different modes:

1.1 per source-destination IP@ pair

In this case all packets corresponding to a given source-destination pair will be forwarded to the same link, so will not be shared between the outgoing links

1.2 per destination IP@

In this case all packets that are to be sent to a given destination (no matter from what source are coming) will be forwarded to the same link, so will not be shared between the outgoing links

1.3 per packet

In this case all packets corresponding to a given destination will be distributed on all the outgoing links, first packet on the first link, second packet on the second link etc, so the packets for the same destination are shared between all the outgoing links.

2) there are 3 different switching modes:

2.1 Fast switching

2.2 Process switching

2.3 CEF switching

3) the above mentioned load-sharing modes and switching modes are interdependent as follows:

1.1 can be used only with CEF

1.2 can be used only with Fast switching

1.3 can be used with either CEF or Process switching

4) How can these 4 configuration (1.1, 1.2, 1.3 with CEF, 1.3 with Process switching) be set in the router?

Giuseppe Larosa · ‎02-22-2009

Hello Petru,

from the configuration point of view configuration is performed at two levels:

some commands are given at node level like

ip cef

then at the single interface level the configuration can be overriden or customized.

different combinations are possible

from

int type x/y

no ip route-cache

no ip route-cache cef

that allows only process switching

I find useful the output of

sh ip interface type x/y | inc flags

that tells you what switching mode is enabled. multiple methods can be active at the same time.

also the commands for per-packet load sharing can be given in interface mode.

Hope to help

Giuseppe

badalam_nt · ‎02-22-2009

Giuseppe, and is my understanding correct regarding:

- load sharing modes

- switching modes

- the link between load sharing modes and switching modes ?

Giuseppe Larosa · ‎02-22-2009

Hello Petru,

I realize that I answered only to your last question.

I think your understanding of the relationships between load sharing modes and the switching modes is correct or at least that I agree with you

Hope to help

Giuseppe