Dar Overview; Ip Packet - 3Com MSR 50 Series Configuration Manual

90

DAR Overview

IP Packet

DAR C
n
DAR only applies to the packets forwarded by IP.
Nowadays, Internet has become the major media for enterprises to implement
their businesses, which has stimulated the business-based applications. The simple
mechanism that only checks IP headers in packets cannot meet the requirements
of current complicated network any longer. Therefore, the concept of Deeper
Application Recognition (DAR) based on businesses has been put forward.
DAR is an intelligent recognition and classification tool that is capable of checking
and recognizing the contents and dynamic protocols from layer 4 to layer 7 (e.g.
BT, HTTP, FTP, RTP) in the packets, in order to distinguish the application-based
protocols. This complements the disadvantage that the packets can only be
classified in a simple way previously.
DAR recognizes different protocols in the following ways:
Protocols such as HTTP, FTP, RTP, RTCP and BitTorrent are recognized by
■
protocol rules. DAR can automatically recognize their dynamic port number;
therefore, these protocols can support both protocol and data packet
matching.
All TCP/UDP protocols except the above mentioned ones are recognized by
■
port number, meaning only protocol packets rather than data packets are
matched.
Recognizing and classifying depth of packets help enhance user's control
granularity on data stream and implement high-priority policy for critical service
data, thus to better protect user's investment.
IP packet format
The IP packet format is shown in
contains 20 bytes, where there are no options.
ONFIGURATION
Figure 476. The header length of IP datagram