This document provides a brief description of expanding your
LAN to encompass 2 additional LANs forming
a WAN or Campus
WAN. Frame Relay and the process for
adding additional Frame Relay connections using Cisco routers
to interconnect at a central connection point or node
router will be discussed.
Figure 1.0 represents the starting base configuration.
Figure 2.0 represents the final result we will achieve.
Scope and Knowledge Level
We will discuss ordering Frame Relay service from your local
Telco, installing and configuring
your Cisco routers, and troubleshooting commands for determining problems with
Frame Relay connection(s).
Network Administrators who have an intermediate understanding
of Networking and Cisco routers IOS software
language are the intended audience for this discussion.
Intricacies of router commands will not be discussed in this text.
Serial links discussed here will be limited to T1
and fractional T1 line speeds.
Readers are expected to start with one node router connected via Frame Relay
back to their ISP's central hub router (see
figure 1.0).
LAN issues (routing issues of TCP/IP
and IPX, for example) will not be covered.
Outcome
Staring with a base configuration,
we will add two sites using Frame Relay links back to the node router to expand
your LAN, linking two additional LANs together to form a Campus
WAN.
Introduction
Frame relay is an encapsulation method that allows users of multiple networks to tie remotessites together using Logical Management Interfaces (LMIs) to map multiple data lines back to one central point or node router. This method creates multiple logical data circuits along one physical data circuit. It is a cost-effective solution that allows ease of management, robust connectivity, lower Telco costs, and simple installation.
Each router connects directly to a CSU/DSU. The CSU/DSU connects to the D-Mark which is the termination point of the copper wire that runs to the Telco office or remote node (in this case the Telco phone switch). The Telco then bundles your circuit with other circuits and ships this data over a larger carrier circuit to where the Frame Relay switch is housed. The larger carrier then splits the circuits apart in a device called a DAX. The DAX delivers your circuit to the frame switch where the magic happens. At this point circuits are joined or diverted to other locations and the definition of the CLOUD become evident.
Note: To use the verification steps described in this
chapter, you must be familiar with Cisco IOS commands and command modes. When
you use the verification steps, you need to change to different command modes.
If you are not familiar with command modes,refer to the "Understanding
Command Modes" section in the "Cisco
IOS Basic Skills" chapter.
External CSU/DSU for node router (2511) capable of line speeds of T1.
External CSU/DSU for router A (2509) capable of line speeds of fractional T1 to T1 speeds. Internal CSU/DSU card for Cisco 1601 series router, router B. Choose 56 Kbps WAN card or the appropriate speed card.
Order a Frame Relay Connection.
Get the circuit ID of your node router circuit (usually written in black ink on the outside cover of the D-Mark). The D-Mark or Smart jack is the circuit termination box the Telco uses to mark the point of demarcation of the data circuit. Call your local Telco and order a Frame Relay circuit for each location. Inform your Telco you wish to have each circuit mapped back to your node router's circuit. Ask for a contact name, telephone number and expected completion date.
When you order is confirmed ask for the Circuit ID (circuit identifier) and
the DLCI (Data Link Connection Identifier)
of each location.
Before you begin have the following information ready:
DLCIs for your new circuits (from Telco)
IP addresses and ranges for all serial and ethernet interfaces
Line speed of your new circuits
Router rip is diabled or version 2 is enabled in your node router
Confirm your node router's IOS is version 10.3.x or later
Configure node router:
config t
ip subnet-zero
ip classless
interface Serial0.2 point-to-point
description Frame-Relay Link to ROUTER A
ip address 203.145.55.1 255.255.255.252
bandwidth 384
frame-relay interface-dlci 51 broadcast
!
interface Serial0.3 point-to-point
description Frame-Relay Link to ROUTER B
ip address 203.145.55.5 255.255.255.252
bandwidth 56
frame-relay interface-dlci 52 broadcast
!
end
write mem
Configure router A:
config t
hostname ROUTER A
!
enable password bert
!
ip subnet-zero
!
interface Ethernet0
ip address 203.145.55.190 255.255.255.192
no shutdown
!
interface Serial0
no ip address
encapsulation frame-relay
bandwidth 56
frame-relay lmi-type ansi
no shutdown
!
interface Serial0.1 point-to-point
description Frame-Relay Link to NODE router
ip address 203.145.55.2 255.255.255.252
bandwidth 56
frame-relay interface-dlci 402 broadcast
!
interface Serial1
no ip address
shutdown
!
router ospf 20
redistribute rip metric 1 subnets
network 203.145.55.0 0.0.0.255 area 0.0.0.0
!
ip name-server 150.199.1.11
ip name-server 128.206.2.252
ip name-server 131.151.254.243
ip classless
ip route 0.0.0.0 0.0.0.0 203.145.55.1
!
snmp-server community public RO
snmp-server trap-authentication
snmp-server location Your City and State
snmp-server contact Your name, email address and phone number
!
line con 0
line aux 0
line vty 0 4
exec-timeout 0 0
password bert
login
!
end
Configure router B:
config t
hostname ROUTER B
!
enable password bert
!
service-module 56k clock source line
service-module 56k network type dds
!
ip subnet-zero
!
interface Ethernet0
ip address 203.145.55.254 255.255.255.192
no shutdown
!
interface Serial0
no ip address
encapsulation frame-relay
bandwidth 56
frame-relay lmi-type ansi
no shutdown
!
interface Serial0.1 point-to-point
description Frame-Relay Link to NODE router
ip address 203.145.55.6 255.255.255.252
bandwidth 56
frame-relay interface-dlci 402 broadcast
!
interface Serial1
no ip address
shutdown
!
router ospf 20
redistribute rip metric 1 subnets
network 203.145.55.0 0.0.0.255 area 0.0.0.0
!
ip name-server 150.199.1.11
ip name-server 128.206.2.252
ip name-server 131.151.254.243
ip classless
ip route 0.0.0.0 0.0.0.0 203.145.55.5
!
snmp-server community public RO
snmp-server trap-authentication
snmp-server location Your City and State
snmp-server contact Your name, email address and phone number
!
line con 0
line aux 0
line vty 0 4
exec-timeout 0 0
password bert
login
!
end
Power up the CSU/DSU and router and confirm there are no test lights on. (Refer to CSU/DSU manufacturer's instructions.)
Router B - Cisco 1601 with Internal 56 Kbps CSU/DSU
You should have configured Router B and added the following configuration
for your CSU/DSU. (If not, go to Configure
Equipment.)
config t
service-module 56k clock source line
service-module 56k network type dds
end
write mem
Connect the supplied RJ45 serial cable to the CSU/DSU and the Telco's D-Mark.
Power up the Router.
Turn Up Frame Relay Links
At this point your equipment should be powered up, configured properly and
attached according to Install
Equipment.
Verify that the Telco's date of commitment for the install is yesterday or before. If too much time has passed, you may need to call your local Telco contact and verify that you are in the process of turning up these links and would like someone to verify that they are ready and not in loop back mode.
If all your configuration changes are correct and the frame-relay links are up and operational you should be able to ping the serial interface IP address of the router on the other end of your Frame Relay link. You should now verify connectivity by trying to ping several devices around and outside your network.
Problems?
Phone your local Telco and inform them that you are turning up the links and ask them to see if they can loop up your CSU/DSU(s).
Do a trace route command (trace 150.199.1.11) from the router and see where your packets die.
If you need assistance in debugging your connection, see troubleshooting
to verify the state of your link.
Step 1
From the ENABLE command mode, enter the show interface serial 0 command or for sub interfaces on the node router type show interface serial 0.1 comand.
Step 2
Confirm that the "Serial0 is up, line protocol is up" message (shown in bold in the example).
1600# show interfaces serial 0 Serial0 is up, line protocol is up
Hardware is QUICC Serial
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation FRAME-RELAY, loopback not set, keepalive set (10 sec)
LMI enq sent 163, LMI stat recvd 136, LMI upd recvd 0, DTE LMI up
LMI enq recvd 39, LMI stat sent 0, LMI upd sent 0
LMI DLCI 1023 LMI type is CISCO frame relay DTE
Broadcast queue 0/64, broadcasts sent/dropped 27/0, interface broadcasts 28
Last input 00:00:01, output 00:00:05, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0 (size/max/drops); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/64/0 (size/threshold/drops)
Conversations 0/1 (active/max active)
Reserved Conversations 0/0 (allocated/max allocated)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1813 packets input, 109641 bytes, 0 no buffer
Received 1576 broadcasts, 0 runts, 0 giants
13 input errors, 0 CRC, 13 frame, 0 overrun, 0 ignored, 0 abort
1848 packets output, 117260 bytes, 0 underruns
0 output errors, 0 collisions, 32 interface resets
0 output buffer failures, 0 output buffers swapped out
29 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
Confirm the interface is receiving a line signal
Step 1
From the ENABLE command mode, enter the "show service module serial 0" command:
1600# show service-module serial 0
Module type is 4-wire Switched 56K in DDS mode,
Current line rate is 56 Kbits/sec and role
is Telco side,
Last clearing of alarm counters 21:23:25
oos/oof : 0, loss of signal: 0,
loss of sealing current: 0,
CSU/DSU loopback : 0,
loopback from remote : 0,
DTE loopback : 0,
line loopback : 0,
Step 2 Confirm that the "loss of signal" message
(shown in bold in the example) shows zero, which means that there are no problems
with the interface receiving a line signal.
input pkts 45 output pkts 52 in bytes 7764
out bytes 9958 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
pvc create time 00:30:59, last time pvc status changed 00:19:21
Step 4
Record the number shown in the "DLCI=" message. (In this example, the number is "17.") You use this number to finish configuring the Frame Relay interface.
Step 5
If there is no output after entering the command, use the show interface serial0 command to determine whether or not the serial interface is active. An example of this command is in the next section, "Configuringthe Point-to-Point Frame Relay Connection." The first line of the command output should be this:
Serial0 is up, line protocol is up
If the first line of the command output is "Serial0 is up, line protocol is down," then you should confirm that the Local Management Interface (LMI) type for the Frame Relay switch is correct by checking for the "LMI type is CISCO" message in the same command output.
Confirm the Frame Relay Maps
Step 1
From the ENABLE command mode, enter the show frame-relay map command.
Step 2
Confirm that the "status defined, active" message (shown in bold in the example) appears for each serial sub interface.
1600# show frame-relay map
Serial0.1 (up): point-to-point dlci, dlci 17(0x11,0x410), broadcast,
status defined, active
Step 3
If the message does not appear, confirm that:
(a) The central site router is connected and configured.
(b) Check with the Frame Relay carrier to verify that the line is operating correctly.
Step 1
From the ENABLE command mode, enter the ping command followed by the IP address of the central site router.
Step 2
Note the percentage in the "Success rate..." line (shown in bold in the example):
1600# ping 192.168.38.40
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.38.40, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 32/32/32 ms
1600#
If the success rate is 10 percent or greater, this verification step is successful.
Confirm the router is talking to the switch and the line is up
Step 1
From the ENABLE command mode, enter the show interface serial 0 command, as follows:
1600# show interfaces serial 0
Serial0 is up, line protocol is up
Hardware is QUICC Serial
MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
Encapsulation FRAME-RELAY, loopback not set, keepalive set (10 sec) LMI enq sent 163, LMI stat recvd 136, LMI upd recvd 0, DTE LMI up
LMI enq recvd 39, LMI stat sent 0, LMI upd sent 0
LMI DLCI 1023 LMI type is CISCO frame relay DTE
Broadcast queue 0/64, broadcasts sent/dropped 27/0, interface broadcasts 28
Last input 00:00:01, output 00:00:05, output hang never
Last clearing of "show interface" counters never
Input queue: 0/75/0 (size/max/drops); Total output drops: 0
Queueing strategy: weighted fair
Output queue: 0/64/0 (size/threshold/drops)
Conversations 0/1 (active/max active)
Reserved Conversations 0/0 (allocated/max allocated)
5 minute input rate 0 bits/sec, 0 packets/sec
5 minute output rate 0 bits/sec, 0 packets/sec
1813 packets input, 109641 bytes, 0 no buffer
Received 1576 broadcasts, 0 runts, 0 giants
13 input errors, 0 CRC, 13 frame, 0 overrun, 0 ignored, 0 abort
1848 packets output, 117260 bytes, 0 underruns
0 output errors, 0 collisions, 32 interface resets
0 output buffer failures, 0 output buffers swapped out
29 carrier transitions
DCD=up DSR=up DTR=up RTS=up CTS=up
Step 2
Confirm that the following messages (shown in bold) appear in the command output:
"Serial0 is up, line protocol is up"
The Frame Relay connection is active.
"LMI enq sent 163, LMI stat recvd 136"
The connection is sending and receiving data. The number shown in your output will probably be different.
"LMI type is CISCO"
The Local Management Interface (LMI) type is configured correctly for the router.
Step 3
If the message does not appear in the command output, take the following
steps:
(a) Confirm with the Telco's Frame Relay service provider that the LMI setting is correct for your line.
(b) Confirm that keepalives are set and that the router is receiving LMI updates.
Confirm the internal CSU/DSU is receiving a line signal
Step 1
From the ENABLE command mode, enter the show service module serial 0 command:
1600# show service-module serial 0
Module type is 4-wire Switched 56K in DDS mode,
Current line rate is 56 Kbits/sec and role is Telco side,
Last clearing of alarm counters 21:23:25
oos/oof : 0, loss of signal : 0,
loss of sealing current: 0,
CSU/DSU loopback : 0,
loopback from remote : 0,
DTE loopback : 0,
line loopback : 0,
Step 2
Confirm that the "loss of signal" message (shown in bold in the example) shows zero, which means that there are no problems with the interface receiving a line signal.
hostname ROUTER A
!
enable password bert
!
ip subnet-zero
!
interface Ethernet0
ip address 203.145.55.190 255.255.255.192
!
interface Serial0
no ip address
encapsulation frame-relay
bandwidth 384
frame-relay lmi-type ansi
!
interface Serial0.1 point-to-point
description Frame-Relay Link to NODE router
ip address 203.145.55.2 255.255.255.252
bandwidth 384
frame-relay interface-dlci 402 broadcast
!
interface Serial1
no ip address
shutdown
!
router ospf 20
redistribute rip metric 1 subnets
network 203.145.55.0 0.0.0.255 area 0.0.0.0
!
ip name-server 150.199.1.11
ip name-server 128.206.2.252
ip name-server 131.151.254.243
ip classless
ip route 0.0.0.0 0.0.0.0 203.145.55.1
!
snmp-server community public RO
snmp-server trap-authentication
snmp-server location Your City and State
snmp-server contact Your name, email address and phone number
!
line con 0
line aux 0
line vty 0 4
exec-timeout 0 0
password bert
login
!
end
hostname ROUTER B
!
enable password bert
!
service-module 56k clock source line
service-module 56k network type dds
!
ip subnet-zero
!
interface Ethernet0
ip address 203.145.55.254 255.255.255.192
!
interface Serial0
no ip address
encapsulation frame-relay
bandwidth 56
frame-relay lmi-type ansi
!
interface Serial0.1 point-to-point
description Frame-Relay Link to NODE router
ip address 203.145.55.6 255.255.255.252
bandwidth 56
frame-relay interface-dlci 402 broadcast
!
interface Serial1
no ip address
shutdown
!
router ospf 20
redistribute rip metric 1 subnets
network 203.145.55.0 0.0.0.255 area 0.0.0.0
!
ip name-server 150.199.1.11
ip name-server 128.206.2.252
ip name-server 131.151.254.243
ip classless
ip route 0.0.0.0 0.0.0.0 203.145.55.5
!
snmp-server community public RO
snmp-server trap-authentication
snmp-server location Your City and State
snmp-server contact Your name, email address and phone number
!
line con 0
line aux 0
line vty 0 4
exec-timeout 0 0
password bert
login
!
end
Console: The terminal used to configure
network devices at boot (start-up) time.
CSU/DSU: Channel Service Unit/Digital
Service Unit
CSMA/CD: Carrier Sence Media Access/Collision
Detection. An IEEE standard of 802.3.
DLCI: Data Link Circuit Identifier - A keep alive mechanism that provides an exchange of information between the network server and the Frame Relay switch to verify data is flowing.
Ethernet: The most popular LAN
technology in use today. The IEEE standard 802.3 defines the rules for configuring
an Ethernet network. It is a 10 Mbps, CSMA/CD
base band network that runs over thin coax, thick coax, twisted pair or fiber
optic cable.
Frame Relay: ANSI/ITU-T-standard
packet interface protocol. You can purchase frame relay lines in increments
between 56 kbps and 1.5 Mbps (equivalent to a T1 connection). The protocol also
has a flat rate billing structure instead of a per hour usage charge. Frame relay
uses the telephone company's shared network on an as needed basis.
Internet: A series of interconnected
local, regional, national and international networks, linked using TCP/IP. Internet
links many government, university and research sites. It provides E-mail,
remote login and file transfer services.
IOS: Internet Operating System - A
proprietary operating system developed by Cisco to interface with their networking
devices.
IP Address: Internet Protocol
address - A uniquely assigned numeric address for each computer connected to the
Internet.
IP: Internet protocol - The Internet
protocol defines how information gets passed between systems across the Internet.
ISP: Internet Service Provider - A
service company that provides you with a user account on a host computer that
has access to the Internet.
Kbps: Kilobits per second.
LAN: Local Area Network - A computer
network located within a relatively limited area, such as a building or a campus.
Line Speed: Expressed in bps, the
maximum rate at which data can reliably be transmitted over a line using given
hardware.
Mbps: Megabits per second.
Node: Any intelligent device connected
to the network. This includes terminal servers, host computers, and any other
devices (such as printers and terminals) that are directly connected to the network.
A node can be thought of as any device that has a "hardware address."
Node router: Central router
that can send and receive information, route and forward information to another
network device.
OSPF: Open Shortest Path First - defined
in RFC 1583, is an Interior Gateway Protocol used to distribute routing information
within a single Autonomous System that supports VLSM (Variable Length Subnet Masking)
to allow efficient IP address use.
Packet: Series of bits containing
data and control information, including source and destination node addresses,
formatted for transmission from one node to another.
Port Multiplier: Concentrator providing
connection to a network for multiple devices.
Protocol: Any standard method
of communicating over a network.
Remote Node: Form of remote access
where the device dialing in acts as a peer on the target network.
Router: Device capable of filtering/forwarding
packets based upon data link layer information. Whereas a bridge or switch
may only read MAC layer addresses to filter, routers are able to read data such
as IP addresses and route accordingly.
Shared Ethernet: Ethernet
configuration in which a number of segments are bound together in a single collision
domain. Hubs produce this type of configuration where only one node can transmit
at a time.
T1: Coined by AT&T for system that
transfers digital signals at 1.544 Mbps.
TCP/IP: Transmission Control Protocol
(TCP) and Internet Protocol (IP) are the standard network protocols in UNIX environments.
They are almost always implemented and used together and called TCP/IP.
Telco: Telephone Company - Your local
Telephone Company service provider.
Telnet: Telnet is an application
that provides a terminal interface between hosts using the TCP/IP network protocol.
It has been standardized so that "telnetting" to any host should give one an interactive
terminal session, regardless of the remote host type or operating system.
Terminal Server: Concentrator
that facilitates communication between hosts and terminals.
Topology: Arrangement of the nodes
and connecting hardware that comprises the network. Types include ring, bus, star
and tree.
Transceiver: Actual device
that interfaces between the network and the local node. The term generally refers
to any connector, such as a MAU, that actively converts signals between the network
and the local node.
WAN: Wide Area Network - Computer network
that covers a large geographical area.
