Check out this blog by Greg Ferro at packet pushers...HTH http://etherealmind.com/cisco-ios-order-of-operation/
David Finnegan From: [email protected] [mailto:[email protected]] On Behalf Of venkat Sent: Saturday, October 30, 2010 2:42 PM To: Taqdir Singh Cc: [email protected] Subject: Re: [OSL | CCIE_RS] Router - Sequence of Steps For L3 Routers: 1. Checksum/CRC is validated for any packet corruption. If corrupted, packets are dropped. 2. Packets are processed only if destination MAC is same as its own interface/VLAN/port-channel MAC. Broadcast and multicast MACs are accepted when appropriate protocols are enabled. 3. Check the CAM table/route-cache for destination and applies any ingress QOS/other policy applied , if configured. 4. while packet has to egress out, TTL value is decremented and check whether decremented TTL value <= 0. If so, packet will be dropped. HTH, Venkat http://ippoint.wordpress.com/ On Sat, Oct 30, 2010 at 10:15 PM, Taqdir Singh <[email protected]<mailto:[email protected]>> wrote: Hi all: Could anyone please list sequence of steps which router performs whenever any packet hits on its interface ? like first it checks destination then its check NAT then its check for any policy then it checks TTL etc ? -- Thanks & regards, Taqdir Singh Networks | 9911709496 _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com<http://www.ipexpert.com> ----------------- This email and any files transmitted with it are confidential and is intended only for the individual named. If you are not the named addressee or if this email is to a user no longer associated with the named address you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately by e-mail if you have received this e-mail by mistake and delete this e-mail from your system. E-mail transmission cannot be guaranteed to be secure or error-free as information could be intercepted, corrupted, lost, destroyed, arrive late or incomplete, or contain viruses. The sender therefore does not accept liability for any errors or omissions in the contents of this message, which arise as a result of e-mail transmission. If verification is required please request a hard-copy version. Please note that any views or opinions presented in this email are solely those of the author and do not necessarily represent those of the company. Finally, the recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email. Arraya Solutions Inc, Suite 113, Plymouth Meeting, PA 19462
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