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New Member

RIP load balancing

hallo

I read that RIP uses ROUND-ROBIN(per-packet) load-balancing over equal-cost paths.

IOS routers can use per-packet (process-switching)or per-destination (fast-switching) load-balancing.

Default is per-destination load-balancing !

So what is the default for RIP ?

best regards

5 REPLIES
Bronze

Re: RIP load balancing

I think it comes down to what is configured on the outgoing interface.

Daniel

Hall of Fame Super Silver

Re: RIP load balancing

Francesco

Actually RIP does not have a default about this and actually does not influence whether it is per packet or per destination. RIP learns routes and puts routes into the forwarding table. RIP is not the process that forwards packets out interfaces toward their destination. It is the process that is forwarding packets toward the destination that determines whether load balancing will be per packet or per destination.

HTH

Rick

New Member

Re: RIP load balancing

Hi RICK,

I read the info about my question in CCNA CNAP Curriculum v.3.1.1 (CCNA2).

So you say that actually the routing protocol is a process and the forwarding is another.

Is this true for every routing protocol other than RIP ?

Have you a doc that explain me better this arguments ?

thanks

francesco

Silver

Re: RIP load balancing

Yes,

The router uses the routing protocols to build the routing table or RIB. You could have multiple routing protocols running on a router, each with its database. All these information are submitted for a single RIB. Rules such as administrative distances and metrics are used to determine which prefixes from each of the routing protocol makes it to the RIB. When there are equal cost routes, then these are installed also into the routing table (by default, up to 4 can be installed). EIGRP supports the instalation of non-equal cost routes in RIB

When a packet arrives on a router destined for a destination, RIB lookup determines the outgoing interface. The process of forwarding the packet is dependent on the switching mechanism running on the router. The switching mechanism builds there cache from the RIB. Check

http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800ca7c9.html

For load balancing, there must be multiple paths available to the destination, hence the routing protocols must have installed more than one entry in the RIB. The actual load balancing is performed by the switching mechanism. This is per-packet and per-destination for process switching and fast switching respectively. CEF supports both, depending on configuration. Check

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094820.shtml

http://www.cisco.com/en/US/products/hw/modules/ps2033/prod_technical_reference09186a00800afeb7.html

http://www.cisco.com/en/US/tech/tk827/tk831/technologies_tech_note09186a0080094806.shtml

New Member

Re: RIP load balancing

thankyou for your response

it helps me to understand better routing process

best regards

francesco

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