Exinda EXNV-10063, Administration Manual

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Exinda Network Orchestrator 3 Using | 306
Match packets with a ToS/DSCP value and apply optimizer polices to this traffic.
Mark the packets with a ToS/DSCP value based on source/destination host/subnet, source/destination port, layer 7
application, time of day, VLAN id, etc.
How to create optimizer policies based on ToS/DSCP value?
For more information, refer to Policies overview (page 292).
How to mark packets with ToS/DSCP value?
For more information, refer to Policies overview (page 292).
The ToS/DiffServ field
The ToS (type of service) or DiffServ (differentiated services) field in the IPv4 header, and the Traffic Class field in the IPv6
header are used to classify IP packets so that routers can make QoS (quality of service) decisions about what path packets
should traverse across the network.
For example, users may want to ensure that VoIP utilizes high quality, low latency (and expensive) links, or, they might
want to ensure email or recreational traffic uses cheaper (but less reliable) links.
Previously, there were 5 different categories that users could classify their traffic with using the IP ToS field (see RFC 791).
Normal Service
Minimize Cost
Maximize Reliability
Maximize Throughput
Minimize Delay
These have since been replaced by a new set of values called DSCP (DiffServ Code Points, see RFC 2474). A DSCP is a 6-
bit number. This provides 64 possible DSCP combinations, of which, only a portion have been standardized and are
listed below.
IPv6 contains an 8 bit Traffic Class field. The 6 most significant bits are treated the same as IPv4 DSCP. The least 2
significant bits are not modified by the appliance.
DSCP Class Name Binary Value Decimal Value
BE (best effort, default) 000000 0
AF11 (assured forwarding, see RFC 2597) 001010 10
AF12 001100 12
AF13 001110 14
AF21 010010 18
AF22 010100 20
AF23 010110 22
AF31 011010 26
AF32 011100 28
AF33 011110 30
AF41 100010 34