Table of Contents

Syntax Description
Keywords
Examples
Related Commands

Frame Relay

This section is used to configure Frame Relay parameters for either the interface specified or for multiple interfaces using the default sections as explained in Appendix , "Default Sections and Default Values."

Syntax Description

WAN slot:port

Ports are numbered starting with 0, so for a module with one port, the port is 0. For theVPN 5008 chassis, slot 0 is the far left slot. For the VPN 5002 chassis, slot 0 is the top slot.

Keywords

After entering the configure command for the section, enter one or more of the following keywords.

MaintProtocol = {AnnexD | AnnexA | LMI | Static}	The MaintProtocol keyword allows you to specify which Frame Relay maintenance protocol is used on the WAN interface. The maintenance protocol is used to send link status and virtual circuit information between Frame Relay switches and other devices (such as routers) that communicate with them. AnnexD is an ANSI standard and is the most commonly used standard in the United states. AnnexD is the default maintenance protocol. AnnexA is a CCITT European standard. LMI was developed by a vendor consortium and is also known as the "consortium" management interface specification. It is still used by some carriers in the United States. Static is a method for using WAN broadcast media (e.g., satellite ground stations) to emulate a Frame Relay network. Do not use this setting for normal Frame Relay switch communications.
PollingFrequency = Number	The PollingFrequency keyword specifies the interval at which the router polls the Frame Relay switch using the maintenance protocol you have selected. The router is required to periodically poll the Frame Relay switch at the remote end of the communications link in order to determine whether the link is active. If any three out of four polls go unanswered by the switch, the router will assume the Frame Relay link is down. Every sixth poll, the router requests a full status packet from the switch in order to update its table of active permanent virtual circuits. The interval is specified in seconds and must be between 5 and 30. The default is 10.
MTU = Number	The keyword MTU allows the MTU (Maximum Transfer Unit) to be configured for the Frame Relay connection. The MTU value must be between 262 and 1700 bytes (except for the MicroRouter 900i and MicroRouter 1000R; the MTU value for these units must be between 262 and 1500 bytes). The default is 1500.
HomeDLCI = Number	The HomeDLCI keyword allows the specification of a DLCI (Data Link Connection Identifier) number for the link when the maintenance protocol is Static. The number is the DLCI value for the router being configured. Each router attached to the emulated network must have a unique DLCI.
DLCI = DLCI_number [IP = {IPAddr | IARP}] [Apple = {Net:Node | IARP}] [IPX = {Net:Node | IARP}]	The keyword DLCI specifies how a network protocol address is mapped to a DLCI on the Frame Relay PVC (Permanent Virtual Circuit). Based on information exchanged between the router and the Frame Relay switch through the maintenance protocol, the router will know the hardware address (the DLCI in this case) but not the protocol address of the remote end of a new PVC. For the PVC to be usable, the router must map the protocol address to the DLCI address either statically or dynamically. The default mapping for all protocols is IARP (Inverse ARP), which allows dynamic mapping and is more flexible and easier to configure than static mapping. IARP, as documented in RFC 1293, functions much like ARP in that when a PVC is first signalled, the Frame Relay station sends out an address request packet. IARP differs from ARP in that the request is for the protocol address rather than the hardware address and is targeted rather than broadcast. When the far end of the PVC receives the request, it replies with the targeted protocol address and the PVC is usable. If a station with multiple protocol addresses assigned to a single interface receives an IARP request, it replies with the host address. This address must be within the requesting station's subnet. If the two stations aren't on the same subnet, the receiving station won't respond and the PVC will remain unusable. DLCI also allows you to create static mappings for the different protocols by specifying the protocol address. DLCI_Number is the decimal address (16-991) which uniquely identifies this end of a PVC. A DLCI number will be provided to you by your Frame Relay carrier for each end of each PVC. The IP IPAddr is the IP address at the remote end of the PVC. It should be a dotted decimal IP address (i.e., 10.1.1.1). If the interface is subnetted, both ends of the PVC must be mapped within the same IP subnet. Static mapping must be used with an IP subinterface (i.e., virtual ports) implementation, because IARP can only resolve a physical port, not a logical subinterface on that port. The Apple Net:Node are a combination of the AppleTalk net and node numbers of the router's WAN interface at the remote end of the PVC (i.e., 33333:2). Net is a decimal AppleTalk net number in the range 1-65279. Node is a decimal AppleTalk node number in the range 1-253. The IPX Net:Node are the IPX net and node numbers of the router's WAN interface at the remote end of the PVC (i.e., FACE0FF:0.0.A5.0.0.1). Net is a hex IPX net number in the range 1-FFFFFFFE. The Node number is an IPX node number specified as a 6-byte hex number separated by dots (.) and represents an Ethernet address. Note   The IPX node address at the remote end is generally a "borrowed" Ethernet address from one of the remote router's Ethernet interfaces. There is no addressing conflict because the actual Ethernet interface is on a network with a different IPX network number.
Compress = {FRF.9_STAC | Off}	The Compress keyword specifies whether Stac LZS compression will be used. LZS compression uses an algorithm to build a history of frequently repeated groups of 8-bit characters and creates shorter bit patterns to represent them. Cisco Systems' current implementation of LZS does not support more than one history. It uses a sequence number and LCB (Longitudinal Check Byte) for error detection. By choosing the Off option, compression is disabled. The default is Off.
PollingFrequency = Number	The PollingFrequency keyword specifies the interval at which the router polls the Frame Relay switch using the maintenance protocol you have selected. The router is required to periodically poll the Frame Relay switch at the remote end of the communications link in order to determine whether the link is active. If any three out of four polls go unanswered by the switch, the router will assume the Frame Relay link is down. Every sixth poll, the router requests a full status packet from the switch in order to update its table of active permanent virtual circuits. The interval is specified in seconds and must be between 5 and 30. The default is 10.

Examples

Set DLCI 16 to Inverse ARP IP on the link.

DLCI=16 IP=IARP
 

Set DLCI 16 to Inverse ARP all protocols recognized on the link.

DLCI=16 IP=IARP IPX=IARP  Apple=IARP  DECnet=IARP
 

Set DLCI 16 to map the protocols to the addresses shown.

DLCI=16 IP=10.1.1.1 IPX=DEAF:0.0.A5.0.0.1 Apple=10:1 DECnet=1.2
 

Related Commands

Command	Description
configure IP	Configures the IP settings for a port
configure Link Config	Configures the interface parameters for a WAN port
show frelay	Shows Frame Relay configuration and statistics

Posted: Wed Sep 27 10:35:12 PDT 2000
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