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Taking a look at diagram below, no CCIE candidate should see anything strange. We have some routers, connected to Frame Relay “cloud”. Over this cloud, they communicate. But, what’s in the cloud? This post explores that…
First of all, let’s take a look at our connectivity. To make things more interesting, I configured EIGRP between R1, R2 and R3.
R1:
R1#show frame-relay map Serial1/0.102 (up): point-to-point dlci, dlci 102(0x66,0x1860), broadcast status defined, active Serial1/0.103 (up): point-to-point dlci, dlci 103(0x67,0x1870), broadcast status defined, active R1#show frame-relay pvc PVC Statistics for interface Serial1/0 (Frame Relay DTE) Active Inactive Deleted Static Local 2 0 0 0 Switched 0 0 0 0 Unused 0 0 0 0 DLCI = 102, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/0.102 input pkts 4092 output pkts 4096 in bytes 332905 out bytes 333949 dropped pkts 0 in pkts dropped 0 out pkts dropped 0 out bytes dropped 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 out bcast pkts 4081 out bcast bytes 332821 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec pvc create time 04:52:05, last time pvc status changed 04:51:35 DLCI = 103, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/0.103 input pkts 4080 output pkts 4094 in bytes 332280 out bytes 334446 dropped pkts 0 in pkts dropped 0 out pkts dropped 0 out bytes dropped 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 out bcast pkts 4073 out bcast bytes 332068 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec pvc create time 04:52:06, last time pvc status changed 04:50:56 R1#show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(123) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 1 13.13.13.3 Se1/0.103 14 04:53:55 33 200 0 11 0 12.12.12.2 Se1/0.102 11 04:54:36 29 200 0 14 R1#show ip route eigrp | begin ^Gateway Gateway of last resort is not set 22.0.0.0/32 is subnetted, 1 subnets D 22.22.22.22 [90/2297856] via 12.12.12.2, 04:54:03, Serial1/0.102 23.0.0.0/24 is subnetted, 1 subnets D 23.23.23.0 [90/2681856] via 13.13.13.3, 04:54:03, Serial1/0.103 [90/2681856] via 12.12.12.2, 04:54:03, Serial1/0.102 33.0.0.0/32 is subnetted, 1 subnets D 33.33.33.33 [90/2297856] via 13.13.13.3, 04:54:03, Serial1/0.103 R1#ping 22.22.22.22 source Loopback0 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 22.22.22.22, timeout is 2 seconds: Packet sent with a source address of 11.11.11.11 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/24/28 ms R1#ping 33.33.33.33 source Loopback0 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 33.33.33.33, timeout is 2 seconds: Packet sent with a source address of 11.11.11.11 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 24/25/28 ms
R2:
R2#show frame-relay map Serial1/0.201 (up): point-to-point dlci, dlci 201(0xC9,0x3090), broadcast status defined, active Serial1/0.203 (up): point-to-point dlci, dlci 203(0xCB,0x30B0), broadcast status defined, active R2#show frame-relay pvc PVC Statistics for interface Serial1/0 (Frame Relay DTE) Active Inactive Deleted Static Local 2 0 0 0 Switched 0 0 0 0 Unused 0 0 0 0 DLCI = 201, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/0.201 input pkts 4113 output pkts 4121 in bytes 334796 out bytes 335966 dropped pkts 0 in pkts dropped 0 out pkts dropped 0 out bytes dropped 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 out bcast pkts 4107 out bcast bytes 334967 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec pvc create time 04:53:40, last time pvc status changed 04:53:10 DLCI = 203, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/0.203 input pkts 4099 output pkts 4105 in bytes 333799 out bytes 334949 dropped pkts 0 in pkts dropped 0 out pkts dropped 0 out bytes dropped 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 out bcast pkts 4097 out bcast bytes 334086 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec pvc create time 04:53:41, last time pvc status changed 04:52:41 R2#show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(123) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 1 23.23.23.3 Se1/0.203 11 04:55:08 23 200 0 9 0 12.12.12.1 Se1/0.201 12 04:55:36 30 200 0 14 R2#show ip route eigrp | begin ^Gateway Gateway of last resort is not set 11.0.0.0/32 is subnetted, 1 subnets D 11.11.11.11 [90/2297856] via 12.12.12.1, 04:55:08, Serial1/0.201 13.0.0.0/24 is subnetted, 1 subnets D 13.13.13.0 [90/2681856] via 23.23.23.3, 04:55:11, Serial1/0.203 [90/2681856] via 12.12.12.1, 04:55:11, Serial1/0.201 33.0.0.0/32 is subnetted, 1 subnets D 33.33.33.33 [90/2297856] via 23.23.23.3, 04:55:08, Serial1/0.203 R2#ping 11.11.11.11 source Loopback0 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 11.11.11.11, timeout is 2 seconds: Packet sent with a source address of 22.22.22.22 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 20/24/28 ms R2#ping 33.33.33.33 source Loopback0 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 33.33.33.33, timeout is 2 seconds: Packet sent with a source address of 22.22.22.22 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/17/20 ms
R3:
R3#show frame-relay map Serial1/0.301 (up): point-to-point dlci, dlci 301(0x12D,0x48D0), broadcast status defined, active Serial1/0.302 (up): point-to-point dlci, dlci 302(0x12E,0x48E0), broadcast status defined, active R3#show frame-relay pvc PVC Statistics for interface Serial1/0 (Frame Relay DTE) Active Inactive Deleted Static Local 2 0 0 0 Switched 0 0 0 0 Unused 0 0 0 0 DLCI = 301, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/0.301 input pkts 4119 output pkts 4124 in bytes 336046 out bytes 337024 dropped pkts 0 in pkts dropped 0 out pkts dropped 0 out bytes dropped 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 out bcast pkts 4104 out bcast bytes 334775 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec pvc create time 04:54:14, last time pvc status changed 04:53:24 DLCI = 302, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial1/0.302 input pkts 4107 output pkts 4114 in bytes 334595 out bytes 335723 dropped pkts 0 in pkts dropped 0 out pkts dropped 0 out bytes dropped 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 out bcast pkts 4106 out bcast bytes 334903 5 minute input rate 0 bits/sec, 0 packets/sec 5 minute output rate 0 bits/sec, 0 packets/sec pvc create time 04:54:14, last time pvc status changed 04:53:24 R3#show ip eigrp neighbors EIGRP-IPv4 Neighbors for AS(123) H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num 1 13.13.13.1 Se1/0.301 11 04:55:53 33 200 0 15 0 23.23.23.2 Se1/0.302 13 04:56:05 639 3834 0 15 R3#show ip route eigrp | begin ^Gateway Gateway of last resort is not set 11.0.0.0/32 is subnetted, 1 subnets D 11.11.11.11 [90/2297856] via 13.13.13.1, 04:56:00, Serial1/0.301 12.0.0.0/24 is subnetted, 1 subnets D 12.12.12.0 [90/2681856] via 23.23.23.2, 04:56:00, Serial1/0.302 [90/2681856] via 13.13.13.1, 04:56:00, Serial1/0.301 22.0.0.0/32 is subnetted, 1 subnets D 22.22.22.22 [90/2297856] via 23.23.23.2, 04:56:00, Serial1/0.302 R3#ping 11.11.11.11 source Loopback0 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 11.11.11.11, timeout is 2 seconds: Packet sent with a source address of 33.33.33.33 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 20/24/28 ms R3#ping 22.22.22.22 source Loopback0 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 22.22.22.22, timeout is 2 seconds: Packet sent with a source address of 33.33.33.33 !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 16/16/16 ms
Excellent, we have the full connectivity, but this wasn’t that hard. Let’s explore what’s in our cloud. Here’s the diagram of the cloud.
I don’t know about you, but to me that looks like one complicated cloud. We have what appear to be 4 Frame Relay switches connected using serial and… Ethernet links! How does that work at all. Well, let’s briefly take a look at relevant configurations on all of them.
FR1:
frame-relay switching ! interface Serial1/0 no ip address encapsulation frame-relay frame-relay lmi-type cisco frame-relay intf-type dce frame-relay route 102 interface Serial1/1 122 frame-relay route 103 interface Serial1/1 143 ! interface Serial1/1 no ip address encapsulation frame-relay frame-relay intf-type nni frame-relay route 122 interface Serial1/0 102 frame-relay route 143 interface Serial1/0 103 !
FR2:
frame-relay switching ! interface Serial1/0 no ip address encapsulation frame-relay frame-relay lmi-type cisco frame-relay intf-type dce frame-relay route 201 interface Serial1/1 122 frame-relay route 203 interface Tunnel24 243 ! interface Serial1/1 no ip address encapsulation frame-relay frame-relay intf-type nni frame-relay route 122 interface Serial1/0 201 frame-relay route 143 interface Tunnel24 143 ! interface Tunnel24 ip unnumbered Loopback0 keepalive 2 6 tunnel source Loopback0 tunnel destination 192.168.0.4 !
FR3: Nothing to see here, this is plain-old-IP-router!
FR4:
frame-relay switching ! interface Serial1/0 no ip address encapsulation frame-relay frame-relay lmi-type cisco frame-relay intf-type dce frame-relay route 301 interface Tunnel24 143 frame-relay route 302 interface Tunnel24 243 ! interface Tunnel24 ip unnumbered Loopback0 keepalive 2 6 tunnel source Loopback0 tunnel destination 192.168.0.2 !
As we can see, not only we can perform Frame Relay switching between serial interfaces, we can also tunnel FrameRelay packets over GRE tunnels. Apart form the displayed configuration, FR2, FR3 and FR4 have very basic OSPF configuration, just to make their Loopback0 interfaces reachable.
You should be able to reproduce this configuration easily using Dynamips/GNS3 or our CCIE Rack Rental. If you have questions, make sure to drop by to our online study community!
–
Marko Milivojevic – CCIE #18427
Senior Technical Instructor – IPexpert
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Tags: CCIE, Frame Relay
Nice explained, did not know about FR over GRE, until now!
WE WANT MORE!!! :)
An I was planning to go to the movies this weekend… Not!
Thanks for this minilab.
I thought you were preparing for CCIE, Lucho? You know that means giving up social life, don’t you? ;-)
–
Marko Milivojevic – CCIE #18427
Senior Technical Instructor – IPexpert
Join our Online Study List
Do we need clock rate?
This was done in Dynamips, so there was no need for that. Otherwise, yes, you need clock rate on the router that has DCE end of the physical cable connected. That may or may not be the Frame Relay DCE!
–
Marko Milivojevic – CCIE #18427
Senior Technical Instructor – IPexpert
Join our Online Study List
Marko
where is the location of DLCI 143 nd 243
It’s on the Tunnel between R2 and R4.
–
Marko Milivojevic – CCIE #18427
Senior Technical Instructor – IPexpert
Join our Online Study List
Very nice blog.
Great article! We want more²