Frame-Relay lab... Can ping others, not self..

ptlinva

Hi Everyone,

I'm about to hit my one year anniversary for my passing my CCENT. I've decided to go back and get my CCNA, so back to techexams.net I go..!! I'm glad to see that you are still here.. It feels good getting my hands "dirty" again!

Today, I'm working on a hub-n-spoke frame-relay network.

PROBLEM: I can ping other routers on the network, but I can't ping myself.

R1: Can ping R2/R3, but not R1's ip address
R2: Can ping R1/R3, but not R2's ip address
R3: Can ping R1/R2, but not R3's ip address

Turning on "debug ip packet" on R1 while pinging R1's address shows...

*Apr 21 01:43:54.338: IP: tableid=0, s=172.12.123.1 (local), d=172.12.123.1 (Serial0/1/0), routed via RIB
*Apr 21 01:43:54.338: IP: s=172.12.123.1 (local), d=172.12.123.1 (Serial0/1/0),len 100, sending
*Apr 21 01:43:54.338: IP: s=172.12.123.1 (local), d=172.12.123.1 (Serial0/1/0),len 100, encapsulation failed.

I see that in the above error message it states "encapsulation failed". Hmm, you've got me... I must be looking right at it...

BTW, if you've made it this far, thank you for your time in taking a look at this. I really do appreciate it.

Your friend in Virginia,
Paul L.

---

Here's the configs...
FRS: (frame-relay router) 3620
=======================
FRS#show run
Building configuration...
Current configuration : 1714 bytes
!
version 12.3
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname FRS
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
ip subnet-zero
!
!
ip host r3 172.12.123.3
ip host r2 172.12.123.2
ip host r1 172.12.123.1
!
ip cef
frame-relay switching
!
!
interface Loopback0
ip address 4.4.4.4 255.255.255.255
!
interface Loopback21
no ip address
!
interface Loopback22
no ip address
!
interface Loopback23
no ip address
!
interface Serial0/0
no ip address
encapsulation frame-relay
logging event subif-link-status
logging event dlci-status-change
serial restart-delay 0
clock rate 56000
no frame-relay inverse-arp
frame-relay intf-type dce
frame-relay route 122 interface Serial0/1 221
frame-relay route 123 interface Serial0/2 321
!
interface Serial0/1
no ip address
encapsulation frame-relay
logging event subif-link-status
logging event dlci-status-change
serial restart-delay 0
clock rate 56000
no frame-relay inverse-arp
frame-relay intf-type dce
frame-relay route 221 interface Serial0/0 122
!
interface Serial0/2
no ip address
encapsulation frame-relay
logging event subif-link-status
logging event dlci-status-change
serial restart-delay 0
clock rate 56000
no frame-relay inverse-arp
frame-relay intf-type dce
frame-relay route 321 interface Serial0/0 123
!
interface Serial0/3
no ip address
serial restart-delay 0
!
interface Ethernet1/0
no ip address
shutdown
half-duplex
!
interface TokenRing1/0
no ip address
shutdown
ring-speed 16
!
ip http server
ip classless
!
!
line con 0
exec-timeout 0 0
logging synchronous
line aux 0
line vty 0 4
login
!
!
end

R1: (the hub) 2801
==============
r1#show run
Building configuration...
Current configuration : 998 bytes
!
version 12.4
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname r1
!
boot-start-marker
boot-end-marker
!
!
no aaa new-model
!
resource policy
!
ip cef
!
!
voice-card 0
!
!
interface FastEthernet0/0
no ip address
shutdown
duplex auto
speed auto
!
interface FastEthernet0/1
no ip address
shutdown
duplex auto
speed auto
!
interface Serial0/1/0
ip address 172.12.123.1 255.255.255.0
encapsulation frame-relay
logging event subif-link-status
logging event dlci-status-change
fair-queue
frame-relay map ip 172.12.123.2 122 broadcast
frame-relay map ip 172.12.123.3 123 broadcast
no frame-relay inverse-arp
!
interface Serial0/2/0
no ip address
!
!
!
no ip http server
no ip http secure-server
!
!
control-plane
!
line con 0
exec-timeout 0 0
logging synchronous
login
line aux 0
line vty 0 4
login
line vty 5 15
login
!
scheduler allocate 20000 1000
end

R2/R3: (spokes) 2600/2500
====================
r2#show run
Building configuration...
Current configuration : 946 bytes
!
version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname r2
!
!
!
!
!
!
ip subnet-zero
no ip finger
!
!
!
!
interface Loopback0
ip address 2.2.2.2 255.255.255.0
!
interface Ethernet0/0
no ip address
shutdown
!
interface Serial0/0
no ip address
shutdown
no fair-queue
!
interface Serial0/1
no ip address
shutdown
!
interface Serial1/0
ip address 172.12.123.2 255.255.255.0
encapsulation frame-relay
logging event subif-link-status
logging event dlci-status-change
no fair-queue
frame-relay map ip 172.12.123.1 221 broadcast
frame-relay map ip 172.12.123.3 221 broadcast
!
interface Serial1/1
interface Serial1/1
!
interface Serial1/2
no ip address
!
interface Serial1/3
no ip address
!
ip classless
no ip http server
!
!
line con 0
exec-timeout 0 0
logging synchronous
transport input none
line aux 0
line vty 0 4
exec-timeout 0 0
logging synchronous
no login
!
end

---

Additional info...
FRS#show frame route
Input Intf Input Dlci Output Intf Output Dlci Status
Serial0/0 122 Serial0/1 221 active
Serial0/0 123 Serial0/2 321 active
Serial0/1 221 Serial0/0 122 active
Serial0/2 321 Serial0/0 123 active

Any suggestions would be GREATLY APPRECIATED!

ptlinva

Okay, I did a "wr er" on all of the routers.

I configured the FRS and R1/R2/R3 just as described on Frame-Relay lab on the TechExams.net website... This time, of course, it wasn't a spoke-n-hub network as routes were configured for all the DLCIs.

Anyway, I've got the same issue...

I can ping the IP assigned to a serial of other routers ...

... but I can't ping the local IP assigned the serial port on a local router.

Hmmm... you've got me...

ptlinva

Okay, I know. I'm talking to myself... it's how I troubleshoot.. <big grin>

I don't remember having this problem when I had this setup about a year ago. I would have remembered not being able to ping the local IP. Hmm, maybe not...

After researching, I found some info at...

Frame Relay Frequently Asked Questions [Frame Relay] - Cisco Systems

Why am I unable to ping my own interface address?

A. You cannot ping your own IP address on a multipoint Frame Relay interface. To make a ping successful on a serial interface, an Internet Control Message Protocol (ICMP) echo request packet must be sent, and an ICMP echo reply packet must be received. Pings to your own interface address are successful on point-to-point subinterfaces or high-level data link control (HDLC) links because the router on the other side of the link returns the ICMP echo and echo reply packets.

The same principle also applies with multipoint (sub) interfaces. To successfully ping your own interface address, another router must send back the ICMP echo request and the echo reply packets. Because multipoint interfaces can have multiple destinations, the router must have Layer 2 (L2) to Layer 3 (L3) mapping for every destination. Because mapping is not configured for our own interface address, the router does not have any L2 to L3 mapping for its own address and does not know how to encapsulate the packet. That is, the router does not know which data-link connection identifier (DLCI) to use to send echo request packets to its own IP address resulting in encapsulation failure. To be able to ping its own interface address, a static mapping must be configured pointing towards another router over the Frame Relay link which can send back the ICMP echo request and reply packets.