Source Routing ?

[t.sriwetchasin]

How to define routing by source ip address ?

[bvsnarayana03]

Pls refer this link:

http://www.cisco.com/en/US/products/ps6599/products_white_paper09186a00800a4409.shtml#wp14035

[Kevin Dorrell]

Please don't confuse "source routing" with "routing by source address".

Source routing is where the originator plants a special header in the packet that specifies which path the packet must take through the network. Most NetAdmins disable it on their routers because it is a security risk.

What you are after is called "policy routing", and it allows you to route according to the source address of the packet, or according to many different parameters if you want, such as precedence etc. etc.

Kevin Dorrell

Luxembourg

[bvsnarayana03]

Hi Kevin,

Nice to see a reply from you.

My understanding was that both the terms refer the same thing.

I would like to learn more about source-routing, why & when is it used. Any links for reference. I tried searching with keyword but no success.

Its really nice to learn from you people.

Thanks

BVS

[nambi_gct]

Hi BVS,

I agree with Kevin.Adding to Kevin's explaination, source routing can be subdivided in to two parts.

1) Strict source routing.

Should go ONLY via the routers mentioned in the header.

2) Loose source routing.

Should go via all the routers mentioned in the header.But additional intermediate hops are allowed.

IP options field was used for this.I am not sure if all the implementations support this.But I guess it was a kind of traffic engineering.

-Nambi

[bvsnarayana03]

Nambi, Kevin

Thanks for the explanation & link. I saw these options in the extended ping, though i used the record option but never tried the others.

It was helpful, thanx.

[Kevin Dorrell]

Source-routing was part of the original IP specification, RFC791 http://www.ietf.org/rfc/rfc0791.txt. Have a look at the options described around page 19. I don't think anyone uses it any more.

Kevin Dorrell

Luxembourg