User Manual

WAN Overview
490 Enterasys X-Pedition User Reference Manual
hardware you have. Each type of interface plays a part in the nomenclature of port identification.
You must use either the “hs.” or “se.” prefix for HSSI and serial interfaces, respectively, when
specifying WAN port identities.
For example, you would specify a frame relay serial WAN port located at router slot 4, port 1, on
VC 100 as “se.4.1.100”.
Using the same approach, a PPP high-speed serial interface (HSSI) WAN port located at router slot
3, port 2 would be identified as “hs.3.2”.
Configuring WAN Interfaces
Configuring IP & IPX interfaces for the WAN is generally the same as for the LAN. As with any IP
network, when you assign an IP/IPX address to each interface and define routing mechanisms such
as OSPF or RIP, you can configure the IP interface on the physical port or you can configure the
interface as part of a VLAN. In the case of IP interfaces, you can configure multiple IP addresses
for each interface. Please refer to Configuring IP Interfaces and Parameters on page 138 and
Configuring IPX Interfaces and Parameters on page 360.
Note: A VLAN containing both LAN and WAN ports will not support interfaces configured
with IPX.
Note: The maximum MTU for WAN interfaces is 1500 bytes.
Special considerations that apply to WAN interfaces are detailed in this section.
Primary and Secondary Addresses
Like LAN interfaces, WAN interfaces can have primary and secondary IP addresses. For Frame
Relay, you can configure primary and secondary addresses which are static or dynamic. For PPP,
however, the primary addresses may be dynamic or static, but the secondary addresses must be
static. This is because the primary addresses of both the local and peer routers are exchanged during
IPCP/IPXCP negotiation.
Note: There is no mechanism in PPP for obtaining any secondary addresses from the peer. For
PPP, IPX network numbers for local and peer routers must match.
Static, Mapped, and Dynamic Peer IP/IPX Addresses
The following sections describe the difference between static, mapped, and dynamic peer IP and
IPX addresses and provide simple command line examples for configuration.