CHABOT COLLEGE CISCO NETWORKING ACADEMY Chabot College Frame Relay Part 1

CHABOT COLLEGE CISCO NETWORKING ACADEMY Frame Relay Overview

CHABOT COLLEGE CISCO NETWORKING ACADEMY Frame Relay Operation Many other WAN technologies (PPP, ATM) can be used inside the FR cloud.

CHABOT COLLEGE CISCO NETWORKING ACADEMY Frame Relay Uses PVCs PVCs have ID numbers called DLCIs. DLCI - Data Link Control Identifier

CHABOT COLLEGE CISCO NETWORKING ACADEMY DLCIs Identify Connections Frame Relay provides a means for statistically multiplexing many logical data conversations (referred to as virtual circuits) by assigning each pair of DTEs connection identifiers.

CHABOT COLLEGE CISCO NETWORKING ACADEMY DLCI A number that identifies the logical circuit between the source and destination device. The FR switch maps the DLCIs between each pair of routers to create a PVC.

CHABOT COLLEGE CISCO NETWORKING ACADEMY DLCIs Can have “local only” significance.

CHABOT COLLEGE CISCO NETWORKING ACADEMY Local Access Rate The clock speed (port speed) of the connection (local loop) to the Frame Relay cloud. It is the rate at which data travels into or out of the network.

CHABOT COLLEGE CISCO NETWORKING ACADEMY Local Management Interface A signaling standard between the CPE device and the FR switch that is responsible for managing the connection and maintaining status between the devices.

CHABOT COLLEGE CISCO NETWORKING ACADEMY Possible LMI Functions keepalive mechanism, which verifies that data is flowing a multicast mechanism which can provide the network server with its local DLCI multicast addressing the ability to give DLCIs global (whole Frame Relay network) significance a status mechanism

CHABOT COLLEGE CISCO NETWORKING ACADEMY Flavors of LMI Different flavors have different features. Currently, ansi is the most common:  cisco  cisco—LMI type defined jointly by Cisco, StrataCom, Northern Telecom, and DEC  ansi—Annex D defined by ANSI standard T1.617  q933a—ITU-T Q.933 Annex A

CHABOT COLLEGE CISCO NETWORKING ACADEMY LMI Configuration Remember to configure your router’s interface to use the same LMI type that the FR provider’s equipment is using. (config-if)#frame-relay lmi-type cisco (config-if)#frame-relay lmi-type ansi (config-if)#frame-relay lmi-type q933a

CHABOT COLLEGE CISCO NETWORKING ACADEMY CIR - Committed Info Rate The rate, in bits per second, that the Frame Relay switch agrees to transfer data. Excess Burst—The maximum number of uncommitted bits that the Frame Relay switch will attempt to transfer beyond the CIR.

CHABOT COLLEGE CISCO NETWORKING ACADEMY DE - Discard Eligibility DE When the router detects network congestion, the FR switch will drop packets with the DE bit set first. The DE bit is set on the oversubscribed traffic; that is, the traffic that was received after the CIR was met.

CHABOT COLLEGE CISCO NETWORKING ACADEMY FECN and BECN Forward explicit congestion notification: When a Frame Relay switch recognizes congestion in the network, it sends an FECN packet to the destination device indicating that congestion has occurred.

CHABOT COLLEGE CISCO NETWORKING ACADEMY FECN and BECN Backward explicit congestion notification: BECN When a Frame Relay switch recognizes congestion in the network, it sends a BECN packet to the source router instructing the router to reduce the rate at which it is sending packets.

CHABOT COLLEGE CISCO NETWORKING ACADEMY FECN and BECN

CHABOT COLLEGE CISCO NETWORKING ACADEMY DLCIs Can be a number between illegal

CHABOT COLLEGE CISCO NETWORKING ACADEMY LMI - Types

CHABOT COLLEGE CISCO NETWORKING ACADEMY Frame Relay Encapsulation The router must be configured to choose which Frame Relay encapsulation will be used.  IETF Encapsulation Type (Most common)  Cisco Encapsulation Type

CHABOT COLLEGE CISCO NETWORKING ACADEMY IETF Frame Relay Frame variable

CHABOT COLLEGE CISCO NETWORKING ACADEMY Inverse ARP

CHABOT COLLEGE CISCO NETWORKING ACADEMY Inverse ARP Inverse ARP The Inverse ARP mechanism allows the router to automatically build the Frame Relay map. The router learns the DLCIs that are in use from the switch during the initial LMI exchange. The router then sends an Inverse ARP request to each DLCI for each protocol configured on the interface if the protocol is supported.

CHABOT COLLEGE CISCO NETWORKING ACADEMY The Frame Relay Map

CHABOT COLLEGE CISCO NETWORKING ACADEMY Frame Relay Operation

CHABOT COLLEGE CISCO NETWORKING ACADEMY Frame Relay Operation

CHABOT COLLEGE CISCO NETWORKING ACADEMY B.S. - Before Subinterfaces Network 8888 Network 7777

CHABOT COLLEGE CISCO NETWORKING ACADEMY Subinterfaces

Subinterfaces

Multipoint Subinterfaces

CHABOT COLLEGE CISCO NETWORKING ACADEMY Point-to-Point Subinterfaces

CHABOT COLLEGE CISCO NETWORKING ACADEMY Autodetects LMI type

CHABOT COLLEGE CISCO NETWORKING ACADEMY FR Verification