RE: f/r and ip i/f's

[Malis_A <[e-mail]>]

To  : IPLPDN Working Group
Date: 26-MAY-1993 15:47:21.00

Dave,

> Has this exchange revealed some omissions in the 
> RFC1294 text? i.e., does it clearly say:

> - When running IP over a f/r net, it is not necessary that all attached IP 
>   interfaces be configured with addresses within a single IP network/subnet

RFC 1294's intention is to standardize encapsulation over FR, not how you set 
up your IP addressing structure.  Using the 1294 encapsulation, you may either 
treat your FR interface as a NBMA network (with all neighbors on the same IP 
subnet), or as a collection of virtual leased-line interfaces -- it's your 
choice.  

These issues are discussed in detail in draft-ietf-ospf-guidelines-frn-00.txt, 
which describes how to set up your IP addressing and route over Frame Relay.

> - At least one IP subnet is requred on the f/r i/f for IP to route over it.

Again, this is strictly a router configuration issue.  For example, you could 
configure a FR PVC as an unnumbered link to another router.  In that case, you 
could certainly router over the interface without having an IP subnet 
associated with it.

These two points are really specific to Fred's implementation rather than 
generic to all router FR interfaces.

> And again in the case of INARP, are the actions Fred recommends clearly
> stated?

For some implementations, Fred's action isn't required.  For example, in Ascom 
Timeplex's implementation, when the Local Management Interface signals the 
presence of a PVC, the router uses Inverse ARP to automatically determine the 
neighbor on the PVC.  The neighbors do not have to be preconfigured (unless you 
explicitly want to preconfigure them).

Cheers,
Andy
____________________________________________________________________________
Andrew G. Malis    [e-mail]                  Ph: [phone]
Ascom Timeplex     289 Great Rd., Acton MA 01720  USA    FAX:[phone]