Extreme Networks Alpine 3804 Hardware Manual page 260

BlackDiamond 6800 Series I/O Modules
• IP unicast forwarding (with selective longest prefix match)
• Destination-sensitive accounting
IP Unicast Forwarding. IP unicast packets are forwarded in the ARM module using the longest prefix
match algorithm. Counts of packets and bytes are maintained based on the routes used to forward
packets.
All IP unicast forwarding is performed on the ARM to facilitate implementation of accounting. When
longest prefix match or accounting is enabled, the ARM, rather than the switch fabric hardware,
performs layer-3 IP unicast forwarding. Layer-2 switching and layer-3 IP multicast forwarding are
unaffected.
ExtremeWare distributes its IP unicast routing table, ARP table, and interface IP addresses to each ARM
so that every ARM contains the same IP routing database.
Each ARM has sufficient capacity to support 239 K IP longest prefix match lookup route entries. Each
route entry also supports up to four equal-cost paths, providing a maximum routing database capacity
of 958 K routes. IP forwarding is configurable per VLAN.
Each ARM IP routing database provides an aggregate IP forwarding throughput of up to 4 Gbps. The
total forwarding throughput for a single BlackDiamond chassis can be scaled up to 16 Gbps by adding
up to four ARM modules. ARMs interface to the BlackDiamond switch fabric via four 1 Gbps internal
links.
See the ExtremeWare Software User Guide for more information about configuring longest prefix matching
on the ARM.
Destination-Sensitive Accounting. Counts of IP packets and bytes are maintained based on the IP
routes used to forward packets. Destination-sensitive accounting gives you the flexibility to bill your
customers at predetermined and different rates. The rates are based on the customers' IP unicast packet
destinations.
Destination-sensitive accounting categorizes IP unicast packets according to two parameters:
• The ID of the VLAN from which the packet was received
• The accounting bin number associated with the route used to forward the packet
For each category, 64-bit counts of both the number of packets and number of bytes forwarded,
excluding those locally delivered to the MSM CPU, are collected. Eight accounting bin numbers, with
values from 0-7, are available for each of the possible 4096 VLAN IDs. This yields a maximum of 32768
sets of accounting statistics.
You use accounting statistics to bill your customers. For a given set of statistics, the source VLAN ID
identifies the customer and the accounting bin number corresponds to a billing rate.
Use the ExtremeWare function to configure policies that assign accounting bin numbers to IP
route-map
routes. Bin zero is the default bin. Any route that does not have an explicit bin assignment via the
function defaults to bin zero.
route-map
You retrieve accounting statistics via the CLI and SNMP.
See the ExtremeWare Software User Guide for more information about configuring destination-sensitive
accounting on the ARM.
260 Extreme Networks Consolidated Hardware Guide