- Enterasys Security Router User's Guide

IP Routing Protocols
5-18 Configuring IP
–Static routes: 1
– BGP external routes: 20
–OSPF intra-area routes: 108
– OSPF inter-area routes: 110
– OSPF external routes: 112
– RIP routes: 120
–BGP internal routes: 200
– Values between 241 and 255 are reserved for internal use
•The
show ip route command displays distances and metrics.
Refer to the XSR CLI Reference Guide for more information on commands.
Static Routes
Static routes are used when a dynamic route to a destination cannot be set up or to specify what
the XSR will route to. The XSR creates static routes with the
ip route command. Refer to the XSR
CLI Reference Guide for more information and sample static route configurations.
The XSR’s Static Route Manager (SRM) allows configuration of multiple static routes to the same
destination but with different hop and distance values. You can cap the number of these routes
with
ip route maximum_multiple.
The SRM validates and forwards all reachable static routes to the Routing Table Manager (RTM)
which saves them but implements only the best (lowest distance) route. Unreachable static routes
are saved in the SRM for later use should they become reachable.
When an interface is enabled, all static routes accessible through that interface are stored in the
RTM. Also, for multi-point interfaces, when a neighbor becomes accessible, all the best static
routes accessible through that neighbor are saved in the RTM. Conversely, when an interface is
disabled, all static routes accessible through that interface are deleted from the RTM. The same
holds true on multi-point interfaces.
VLAN Routing
Virtual Local Area Networks (VLANs) allow groups of end systems, possibly on multiple physical
LAN segments, to communicate as if they were a common LAN unconstrained by the network's
physical layout. VLAN switches can be used to establish different broadcast domains within
networks but different VLANs cannot communicate with one another through VLAN switches
because routing is still required for inter-VLAN traffic. The XSR’s VLAN route traffic among IEEE
802.1Q VLANs.
The IEEE 802.1Q standard documents the insertion of a VLAN tag, shown in Figure 5-1, between
the Source MAC address and the Length/Type of an Ethernet frame to identify the VLAN to
which the frame belongs.