14 module
TRANSCRIPT
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Establishing a Frame Relay PVC Connection
Chapter 14
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Objectives
• Determine how Frame Relay operates
• Configure Frame Relay
• Configure Frame Relay subinterfaces
• Verify Frame Relay operation
Upon completion of this chapter, youwill be able to perform the following tasks:
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Frame Relay Overview
• Virtual circuits make connections
• Connection-oriented service
DTE or CPE router
Frame Relay works here.TokenRing
CSU/DSU
DCE or FrameRelay Switch
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Frame Relay Stacks
OSI Reference Model
Application
Presentation
Session
Transport
Network
Data Link
Physical
Frame Relay
IP/IPX/Apple Talk, etc
Frame Relay
EIA/TIA-232, EIA/TIA-449, V.35, X.21, EIA/TIA-530
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Frame Relay Terminology
Local AccessLoop=T1
DLCI=400
DLCI=500
LMI500=Active400=Active
Local AccessLoop=64 kbps
Local AccessLoop=64 kbps
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Frame Relay Address Mapping
• Get locally significant DLCIs from provider
• Map your network addresses to DLCIs
Frame Relay map
CSU/DSU
10.1.1.1
DLCI:500 PVC
Inverse ARP or
IP
(10.1.1.1)
Frame
RelayDLCI (500)
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
CSU/DSU
10.1.1.1
DLCI:500PVC
Frame Relay Signaling
PVCDLCI:400
Keepalive
Cisco supports three LMI standards:
• Cisco
• ANSI T1.617 Annex D
• ITU-T Q.933 Annex A
LMI
500=Active
400=Inactive
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Frame Relay Operation
Frame RelayCloud
2
DLCI=100DLCI=400
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
3Status Inquiry
3Status Inquiry
Frame RelayCloud
2
DLCI=100DLCI=400
172.168.5.5172.168.5.7
Frame Relay Inverse ARP and LMI Operation
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
4DLCI 400=Active
4DLCI 100=Active
3Status Inquiry
3Status Inquiry
Frame RelayCloud
2
DLCI=100DLCI=400
172.168.5.5172.168.5.7
Frame Relay Inverse ARP and LMI Operation
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Frame Relay Inverse ARP and LMI Operation
4DLCI 400=Active
4DLCI 100=Active
3Status Inquiry
3Status Inquiry
Frame RelayCloud
2
DLCI=100DLCI=400
172.168.5.5172.168.5.7
5 Hello, I am 172.168.5.5 on DLCI 100, who are you?
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Frame Relay Map
172.168.5.5 DLCI 400 Active6
Frame RelayCloudDLCI=100
DLCI=400
Frame Relay Inverse ARP and LMI Operation (cont.)
172.168.5.5 172.168.5.7
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Hello, I am 172.168.5.7 on DLCI 400.5
Frame Relay Map
172.168.5.5 DLCI 400 Active6
Frame RelayCloudDLCI=100
DLCI=400
Frame Relay Map
172.168.5.7 DLCI 100 Active6
172.168.5.7172.168.5.5
Frame Relay Inverse ARP and LMI Operation (cont.)
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
7 Hello, I am 172.168.5.5 on DLCI 100.
Hello, I am 172.168.5.7 on DLCI 400.5
6Frame Relay Map
172.168.5.5 DLCI 400 Active
Frame RelayCloudDLCI=100
DLCI=400
Frame Relay Map
172.168.5.7 DLCI 100 Active6
172.168.5.7172.168.5.5
Frame Relay Inverse ARP and LMI Operation (cont.)
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
8 Keepalive Keepalive 8
Frame Relay Inverse ARP and LMI Operation (cont.)
7 Hello, I am 172.168.5.5 on DLCI 100.
Hello, I am 172.168.5.7 on DLCI 400.5
6Frame Relay Map
172.168.5.5 DLCI 400 Active
Frame RelayCloudDLCI=100
DLCI=400
Frame Relay Map172.168.5.7 DLCI 100 Active6
172.168.5.7172.168.5.5
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Configuring Basic Frame Relay
HQBranch
Rel. 11.2 RouterRel. 10.3 Router
interface Serial1ip address 10.16.0.1 255.255.255.0encapsulation frame-relaybandwidth 64
interface Serial1ip address 10.16.0.2 255.255.255.0encapsulation frame-relaybandwidth 64frame-relay lmi-type ansi
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Configuring Basic Frame Relay (cont.)
HQBranch
Rel. 11.2 RouterRel. 10.3 Router
Inverse ARP is• enabled by default • does not appear in configuration output.
interface Serial1ip address 10.16.0.1 255.255.255.0encapsulation frame-relaybandwidth 64
interface Serial1ip address 10.16.0.2 255.255.255.0encapsulation frame-relaybandwidth 64frame-relay lmi-type ansi
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Selecting a Frame Relay Topology
Star (Hub and Spoke)
Full Mesh
Partial Mesh
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
• Broadcast traffic must be replicated for each active connection
Reachability Issues with Routing Updates
RoutingUpdate
A
Circuit #21
Circuit #22
Circuit #23
D
C
B
B
C
D
2
3
1
Problem:
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Resolving Reachability Issues
• Split horizon can cause problems in NBMA environments
• A single physical interface simulates multiple logical interfaces
• Subinterfaces can resolve split horizon issues
Subnet A
Subnet B
Subnet C
S0
PhysicalInterface
S0.1S0.2S0.3
Logical Interface
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Configuring Subinterfaces
• Multipoint–Subinterfaces act as default NBMA network
–Can save subnets because uses single subnet
–Good for full-mesh topology
• Point-to-Point–Subinterfaces act as leased line
–Each point-to-point connection requires its own subnet
–Good for star or partial-mesh topologies
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Configuring Subinterfaces (cont.)
RTR1
s0.2-DLCI=110
s0.3-DLCI=120
s0.1s0.2
RTR3
s0.1
s0.3RTR2
<Output Omitted>interface Serial0 no ip address encapsulation frame-relay!interface Serial0.2 point-to-point ip address 10.17.0.1 255.255.255.0 bandwidth 64 frame-relay interface-dlci 110!interface Serial0.3 point-to-point ip address 10.18.0.1 255.255.255.0 bandwidth 64 frame-relay interface-dlci 120!router rip network 10.0.0.0<output omitted>
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Multipoint Subinterfaces Configuration Example
RTR1
RTR3
RTR2
RTR4
s2.1=10.17.0.2/24
s2.2=10.17.0.1/24
s2.1=10.17.0.4/24
s2.1=10.17.0.3/24
2Copyright © 1998, Cisco Systems, Inc.ICRC_revision_11.3
Multipoint Subinterfaces Configuration Example
<Output Omitted>!interface Serial2 no ip address encapsulation frame-relay!interface Serial2.2 multipoint ip address 10.17.0.1 255.255.255.0 bandwidth 64 frame-relay map ip 10.17.0.2 120 broadcast frame-relay map ip 10.17.0.3 130 broadcast frame-relay map ip 10.17.0.4 140 broadcast!router rip network 10.0.0.0<Output Omitted>
2Copyright © 1998, Cisco Systems, Inc.ICRC_rev isi on_11.3