CCIE Pursuit Blog

April 28, 2008

Internetwork Expert Volume II: Lab 5 – Section 1

WAN Technologies – 9 Points

1.1 Partial Mesh Frame Relay

IE switched up the order in this lab and started with Frame Relay.  I skipped ahead and did section 2 (Bridging and Switching) first and then returned to this section.

Easy task.  First time that I’ve seen IE use a dedicated DLCI between two spokes (well…’would be spokes’).

“Traffic from r5 destined for r2 should transit r4.”

Traffic will follow this path:

R5 (504) -> (405) r4 (403) -> (304) r3 (302) -> (203) r2.

r5#trace 162.1.0.2

Type escape sequence to abort.
Tracing the route to 162.1.0.2

  1 162.1.0.48 msec 4 msec 4 msec
  2 162.1.0.3 4 msec 4 msec 4 msec
  3 162.1.0.28 msec *  4 msec

1.2 Point-to-Point Frame Relay

Easy task.

1.3 Point-to-Point Frame Relay

Interesting task.  You need to match this Frame mapping on r6:

r6#sh frame map
Serial0/0.1(up): ip 54.1.1.254 dlci 101(0x65,0x1850), dynamic,
              broadcast,, status defined, active

So you need to use a subinterface as well as Frame Inverse-ARP.  That means that you’ll need to use a multipoint subinterface as inarp will not run on a point-to-point subinterface.

r6#sh run | sec l0/0
interface Serial0/0
 no ip address
 encapsulation frame-relay
interface Serial0/0.1 multipoint
 ip address 54.1.1.6 255.255.255.0
 frame-relay interface-dlci 101

1.4 PPP

“…configure r4 and r5 to support reliable transport over the circuit.”

???

A quick search of the (12.3) Master Command Index for the term ‘reliable’ pulled this up:

ppp reliable-link

You can use the show interface command to determine whether LAPB has been established on the link. You can troubleshoot PPP reliable link by using the debug lapb command and the debug ppp negotiations, debug ppp errors, and debug ppp packets commands.

r4#sh int s0/1 | sec LAPB
  LAPB DTE, state CONNECT, modulo 8, k 7, N1 12048, N2 3
      T1 3000, T2 0, interface outage (partial T3) 0, T4 0, PPP over LAPB
      VS 3, VR 3, tx NR 3, Remote VR 3, Retransmissions 0
      Queues: U/S frames 0, I frames 0, unack. 0, reTx 0
      IFRAMEs 19/19 RNRs 0/0 REJs 0/0 SABM/Es 1/1 FRMRs 0/0 DISCs 0/0, loopback not set

r5#sh int s0/1 | sec LAPB
  LAPB DCE, state CONNECT, modulo 8, k 7, N1 12048, N2 3
      T1 3000, T2 0, interface outage (partial T3) 0, T4 0, PPP over LAPB
      VS 0, VR 0, tx NR 0, Remote VR 0, Retransmissions 0
      Queues: U/S frames 0, I frames 0, unack. 0, reTx 0
      IFRAMEs 32/32 RNRs 0/0 REJs 0/0 SABM/Es 1/1 FRMRs 0/0 DISCs 0/0, loopback not set

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