Hey! If my understanding is correct, Without the qos pre-classify command, packets traversing across the same tunnel have the same tunnel header. ie) by default tunneing function won't copy orginal ip header to tunnel header
But in some materials i have seen, that the tos copying is the function of tunneling mechnicam and not by qos-preclassify command. And if our classification option matches only on the TOS byte then don't need to use qos-preclassify command.
You are absolutely right. If you set your queuing based on the ToS byte in your IP packet , youwouldnt need pre classification. The Tos Bye is copied from the original IP header to the new header being formed. This is true for both GRE as well asIpSec tunnels.But if you matched the IP addresses (using access-lists), then you will have to do preclassification so that classification is done bfor encapsulation
Table of ContentsIntroductionVersion HistoryPossible Future
UpdatesDocuments PurposeNAT Operation in ASA 8.3+ SectionsRule Types
Network Object NATTwice NAT / Manual NATRule Types used per SectionNAT
Types used with Twice NAT / Manual NAT and Network Obje...
Table of Contents Introduction:This document describes details on how
NAT-T works. Background: ESP encrypts all critical information,
encapsulating the entire inner TCP/UDP datagram within an ESP header.
ESP is an IP protocol in the same sense that TCP an...