User`s guide

122 XSR User’s Guide
Multi-Protocol Encapsulation Chapter 7
Configuring Frame Relay
 Multi-protocol interconnect over Frame Relay - RFC-2427. Only IP is
supported.
 RFC-2390 Frame Relay Inverse ARP.
 Multiple logical interfaces over the same physical Frame Relay port
(sub-interfaces).
 Quality of Service: standard FIFO queuing, or IP QoS on DLCIs.
 Max PDU size of 1500 bytes.
 Industry-standard CLI and statistics.
The XSR proscribes the following maximum configuration limits with
standard memory installed (64 Mbytes):
 30 Frame Relay interfaces or sub-interfaces per node.
 300 DLCIs per node.
 30 Frame Relay map-classes.
Multi-Protocol Encapsulation
XSR supports encapsulation of multiple protocols - a flexible way to carry
many protocols via Frame Relay. This method is useful when it is necessary to
multiplex/de-multiplex across one Frame Relay connection, as described by
RFC-2427, which defines a generic, end-to-end encapsulation mechanism for
devices to communicate many protocols over a single port.
Address Resolution
The XSR supports dynamic resolution via Inverse ARP to map virtual circuits
(DLCI) to remote protocol addresses, as defined in RFC-2390.
Dynamic Resolution Using Inverse ARP
Inverse ARP allows a network node to request a next hop IP address
corresponding to a given hardware address. Technically, this applies to Frame
Relay nodes that may have a Data Link Connection Identifier (DLCI), the
Frame Relay equivalent of a hardware address, associated with an established
Permanent Virtual Circuit (PVC), but do not know the IP address of the node
on the other side of the connection.