Qos With Vlan; Policy Based Routing; Accessing The Global Routing Policy Table - Enterasys Security Router X-PeditionTM User Manual

IP Routing Protocols
For sample configurations, refer to

QoS with VLAN

The XSR's support for Quality of Service (QoS) with VLAN is described in the chapter
"Configuring Quality of Service"

Policy Based Routing

IP packets typically are forwarded according to the route chosen by traditional routing protocols
RIP, OSPF, BGP or static routes. Selection is based only on the destination of the packet. Policy
Based Routing (PBR) allows you to selectively forward some patterned packets through alternative
paths. It is not meant to replace routing protocols but is complementary while adding flexibility. If
any packets do not meet policy criteria, the destination-based routing table will be searched.
PBR is beneficial for the following reasons:
• Flexible Transit Provider Selection - Internet service providers and others can set priorities for
their customers and use PBR to route traffic according to their users' priorities through
different Internet connections across policy routers.
• Cost Savings - PBR can cut networking costs by distributing traffic among low-cost and high-
cost paths.
• Load Sharing - You can implement policies to distribute traffic among multiple paths based on
traffic characteristics as opposed to traditional load sharing. With PBR, the same traffic flow
will go through the same path but different traffic flow will be directed over a different path
according to the policy.

Accessing the Global Routing Policy Table

Policy-based routing can be applied to incoming packets only and can be enabled on any interface
with the
1. If a packet is a candidate for PBR, the XSR consults a global routing policy table in the form of
a route-map table having multiple entries. Each entry is assigned a sequence number and are
sequentially ordered from low to high. The
number and acquires PBR configuration mode. You can display this information with the
show route-map pbr
5-22 Configuring IP
Figure 5-7
2
IP 3.2.3.4/24
PPP encapsulation
PPP IP: 9.9.9.1
Serial 1
Incoming Serial frame
1
Note: Policy-based routing takes precedence over destination-based routing.
ip policy command. It works as follows:
command.
WAN Interface to VLAN Ethernet Topology
IP Routing Table
1.2.3.0/24 F1.1
3.3.2.0/24 Serial 1
9.9.9.0/24 Serial 1 (Static)
F1.1
Ethernet VLAN Tag IP: 9.9.9.1
Priority CFI
"Configuring VLAN Examples"
on page 12-1.
route-map pbr
VLAN 1200
IP 1.2.3.4/24
3
VLAN: 1200
Outgoing VLAN tagged frame
on page 5-46.
command specifies the sequence