WB II: Lab14 - Task 1.7 - Point-to-Point Addressing

I used Serial i/f with unnumbered and loopback i/f 45 between R4 and R5. However, solution guide (SG) used serial i/f + multilink i/f + loopback i/f 45.

interface loopback 45

 ip a.a.a.a m.m.m.m

interface multilink 1

 ip unnumbered loopback 45

interface serial 0/1
 encap ppp
 ppp multilink

 ppp multilink group 1

 clock rate 64000

According the restriction section from this link this shouldn't be a problem. The thing is I don't see task related to interleaving but I can see the differenences between using ip unnumbered directly on the serial interface and using multilink interface and this differenece is if you are using multilink the only type of routes you can see are /32 but if you use ip unnumbered on the ppp interface directly there is one /31 route in the fib,however, if that's what they want in this case then probably the wording is not correct.


http://www.cisco.com/en/US/docs/ios/12_2/qos/configuration/guide/qcflfi.html

Restrictions

Interleaving applies only to interfaces that can configure a multilink bundle interface. These interfaces include virtual templates, dialer interfaces, and ISDN BRI or PRI interfaces.

Multilink and fair queueing are not supported when a multilink bundle is off-loaded to a different system using Multichassis Multilink PPP (MMP). Thus, interleaving is not supported in MMP networking designs.