frame-relay multipoint vs point-to-point

acidsatyr

Hello,

configuration wise, what is the difference between defining a serial subinterface as point-to-point vs multilink?
int s1/0.555 point-to-point
int s1/0.555 multipoint

I can still treat multipoint as point-to-point using frame-relay interface-dlci 555 for example.
So what is the difference and when should one be used instead of other?

Thx

Forsaken_GA

that's not as simple a question as you might think.

From a practical standpoint, the biggest differences are how each type handles inverse arp and what type of network they present themselves as.

point to point links are treated like point to point links (duh).

multipoint links present themselves as multiaccess medium. This has implications for OSPF, as it will treat it as an NBMA network by default, which alters it's behavior

If all your routers need to be on the same logical subnet, you use multipoint, if all your routers can be addressed with individual subnets, you use point to point.

acidsatyr

Hey forsaken,

I've just tried to do 'frame map ip x.x.x.x dlci' on a serial point-to-point...and failed! So, building on what you said you must in fact use multipoint if you want to use map command. This is really weird because on my other, albeit much older IOS you COULD type in map command on point-to-point.
I guess that settles that than!

Forsaken_GA

well, on a point to point, it doesn't need a map or inverse arp. It's a point to point link, so it just assumes that whatever IP you're trying to reach needs to be shunted down the dlci it's configured for