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BigIron RX Series Configuration Guide
573
53-1002253-01
Chapter
22
Policy-Based Routing
Policy-Based Routing (PBR)
Policy-Based Routing (PBR) allows you to use ACLs and route maps to selectively modify and route
IP packets in hardware. The ACLs classify the traffic. Route maps that match on the ACLs set
routing attributes for the traffic.
A PBR policy specifies the next hop for traffic that matches the policy. Using standard ACLs with
PBR, you can route IP packets based on their source IP address. With extended ACLs, you can
route IP packets based on all of the clauses in the extended ACL.
You can configure the device to perform the following types of PBR based on a packet’s Layer 3 and
Layer 4 information:
•
Select the next-hop gateway.
•
Send the packet to the null interface (null0).
When a PBR policy has multiple next hops to a destination, PBR selects the first live next hop
specified in the policy that is up. If none of the policy's direct routes or next hops are available, the
packet is routed in the normal way.
Configuration considerations
•
A PBR policy on an interface takes precedence over a global PBR policy.
•
You cannot apply PBR on a port if that port already has ACLs, ACL-based rate limiting, or
TOS-based QoS.
•
The number of route maps that you can define is limited by the system memory. When a route
map is used in a PBR policy, the PBR policy uses up to 6 instances of a route map, up to 6 ACLs
in a matching policy of each route map instance, and up to 6 next hops in a set policy of each
route map instance.
•
ACLs with the log option configured should not be used for PBR purposes.
•
PBR ignores explicit or implicit deny ip any any ACL entries, to ensure that for route maps that
use multiple ACLs, the traffic is compared to all the ACLs. PBR also ignores any deny clauses in
an ACL. Traffic that matches a deny clause is routed normally using Layer 3 paths.
•
PBR always selects the first next hop from the next hop list that is up. If a PBR policy's next hop
goes down, the policy uses another next hop if available. If no next hops are available, the
device routes the traffic in the normal way.
•
PBR is not supported for fragmented packets. If the PBR’s ACL filters on Layer 4 information
like TCP/UDP ports, fragmented packed are routed normally.
•
You can change route maps or ACL definitions dynamically and do not need to rebind the PBR
policy to an interface.
•
The CAM can hold up to 1024 ACL, PBR, and Rate Limiting entries and this maximum is divided
as follows:
Содержание BigIron RX Series
Страница 100: ...24 BigIron RX Series Configuration Guide 53 1002253 01 Logging on through the Web Management Interface 2 ...
Страница 192: ...116 BigIron RX Series Configuration Guide 53 1002253 01 Configuring authentication method lists 4 ...
Страница 228: ...152 BigIron RX Series Configuration Guide 53 1002253 01 Enabling WAN PHY mode support 6 ...
Страница 312: ...236 BigIron RX Series Configuration Guide 53 1002253 01 Displaying IP information 7 ...
Страница 356: ...280 BigIron RX Series Configuration Guide 53 1002253 01 Resetting LLDP statistics 9 ...
Страница 402: ...326 BigIron RX Series Configuration Guide 53 1002253 01 Transparent firewall mode 11 ...
Страница 432: ...356 BigIron RX Series Configuration Guide 53 1002253 01 SuperSpan 12 ...
Страница 500: ...424 BigIron RX Series Configuration Guide 53 1002253 01 MRP CLI example 14 ...
Страница 580: ...504 BigIron RX Series Configuration Guide 53 1002253 01 Configuring multicast traffic engineering 18 ...
Страница 591: ...BigIron RX Series Configuration Guide 515 53 1002253 01 Displaying traffic reduction 19 ...
Страница 592: ...516 BigIron RX Series Configuration Guide 53 1002253 01 Displaying traffic reduction 19 ...
Страница 598: ...522 BigIron RX Series Configuration Guide 53 1002253 01 Viewing Layer 2 ACLs 20 ...
Страница 656: ...580 BigIron RX Series Configuration Guide 53 1002253 01 Trunk formation 22 ...
Страница 754: ...678 BigIron RX Series Configuration Guide 53 1002253 01 Displaying RIP filters 24 ...
Страница 814: ...738 BigIron RX Series Configuration Guide 53 1002253 01 Displaying OSPF information 25 ...
Страница 932: ...856 BigIron RX Series Configuration Guide 53 1002253 01 Generalized TTL security mechanism support 26 ...
Страница 980: ...904 BigIron RX Series Configuration Guide 53 1002253 01 Clearing IS IS information 28 ...
Страница 1000: ...924 BigIron RX Series Configuration Guide 53 1002253 01 Using secure copy 30 ...
Страница 1088: ...1012 BigIron RX Series Configuration Guide 53 1002253 01 IP source guard 35 ...
Страница 1108: ...1032 BigIron RX Series Configuration Guide 53 1002253 01 Reading CDP packets 37 ...
Страница 1126: ...1050 BigIron RX Series Configuration Guide 53 1002253 01 Clearing sFlow statistics 39 ...
Страница 1140: ...1064 BigIron RX Series Configuration Guide 53 1002253 01 802 1s Multiple Spanning Tree Protocol 40 ...
Страница 1324: ...1248 BigIron RX Series Configuration Guide 53 1002253 01 Displaying OSPFv3 information 48 ...
Страница 1363: ...BigIron RX Series Configuration Guide 1287 53 1002253 01 Continuous System Monitor 51 ...
Страница 1364: ...1288 BigIron RX Series Configuration Guide 53 1002253 01 Continuous System Monitor 51 ...
Страница 1404: ...1328 BigIron RX Series Configuration Guide 53 1002253 01 Commands That Require a Reload D ...
Страница 1458: ...1382 BigIron RX Series Configuration Guide 53 1002253 01 VSRP E ...