Re: [LIP] IP module xmitting packets
Amit Kucheria <[email protected]>
| Newsgroups | gmane.user-groups.linux.india.programmers |
|---|---|
| Message-ID | <[email protected]> |
On Tue, 13 Jan 2004, suresh kumar wrote: > > Hi, When the packets are being sent out from the linux system, ip > module first sees if there exists a routing cache entry and if not it > will see the fib creates an routing cache entry and xmits the packet > in the respective interface. So for each connection if it creates a > routing cache entry and if it first checks for the subsequent packets, > I think it is a bit costly than checking fib i.e. routing table. One > reason which I could find for TCP connections is, routing cache helps > in keeping track of the TCP state information and for all the other As far as i can remember, the routing cache did not keep track of TCP connection state (that is the job of the TCP state machine). The routing cache is used for exactly what its name signifies: routing. > protocols to know which ports are being in use which can be viewed by > netstat. (correct me if I am wrong). apart from the mentioned reasons, > is there ne other reason for it to maintain routing cache entry > especially in case of UDP. cheers Suresh V.V Suresh Kumar I dont think the routing cache cares about TCP/UDP. It simply indexes (hashes) the routes based on source, destination and TOS values. See rt_hash_code(). /Amit -- I'm an angel!!! Honest! The horns are just there to hold the halo up straight. ----------------------------------------------------- Amit Kucheria | amitk@ NOSPAM ittc.ku.edu Wireless Systems Engineer | 760-822-8529 Metric Systems Corp. | Vista, CA 92083 ----------------------------------------------------- ------------------------------------------------------- This SF.net email is sponsored by: Perforce Software. Perforce is the Fast Software Configuration Management System offering advanced branching capabilities and atomic changes on 50+ platforms. Free Eval! http://www.perforce.com/perforce/loadprog.html