Huawei Quidway S7700 Configuration Manual - Qos page 30

Quidway S7700 Smart Routing Switch
Configuration Guide - QoS
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Issue 01 (2011-07-15)
CAUTION
After the redirect cpu command is used, the packets matching the traffic classification rule
are redirected to the CPU, causing deterioration of CPU performance. Use the redirect
cpu command with caution.
redirect [ vpn-instance vpn-instance-name ] ip-nexthop ip-address &<1-4>
The packets matching the traffic classification are redirected to the next hop.
If multiple next hop IP addresses are configured, the S7700 redirects packets in active/
standby mode. A maximum of four next hop IP addresses can be configured in a traffic
behavior. The S7700 determines the primary path and backup paths according to the sequence
in which next hop IP addresses were configured. The next hop IP address that was configured
first has the highest priority and this next hop is used as the primary path. Other next hops
are used as backup paths. When the primary path is Down, the backup path with the highest
priority is used as the primary path.
NOTE
The policy-based routing function can be implemented by configuring redirection.
redirect ip-multihop { nexthop ip-address } &<2-4>
The packets matching the traffic classification are redirected to one of the multiple next hops.
If multiple next hops are specified, the S7700 redirects packets through the equal-cost routes
that work in load balancing mode. That is, the S7700 selects a next hop by using the Hash
algorithm based on the source IP addresses of the packets, regardless of the traffic volume.
If the source IP addresses of the packets are the same, the S7700 forwards the packets to the
same next hop regardless of the traffic volume.
When redirecting packets to multiple next hops, the S7700 can quickly switch the link to an
available outbound interface by using the Hash algorithm if the outbound interface
corresponding to the current next hop becomes Down or the route changes suddenly.
If no ARP entry corresponding to the next hop address is matched on the device, the redirect
ip-multihop command can be run successfully. The S7700 forwards the packets to the
original destination. The redirection function, however, is invalid until there is the
corresponding ARP entry on the device.
redirect interface interface-type interface-number
The packets matching the traffic classification are redirected to a specified interface.
redirect lsp public dest-address { nexthop-address | interface interface-type
interface-number | secondary }
The packets matching the traffic classification are redirected to the public LSP.
redirect multi-trunk { eth-trunk trunk-id } &<1-4>
The packets matching the traffic classifier are redirected to multiple Eth-Trunks.
If the inbound interface is the high-speed interface (for example, XGE interface) but the
outbound interface is the low-speed interface (for example, GE interface), packets need to
be redirected to physical interfaces of multiple Eth-Trunks. The traffic can be load balanced
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1 Class-based QoS Configuration
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