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New Member

EIGRP Flag 0x9 (What is it)

All,

I have observed that when a router sends an update, it sets the eigrp flag bit in some of the sending update packets.

Please could someone elaborate what 0x9 is and what it is used for.

We know about 0x1 and 0x2. Also, are there any more flags that we should know about?

example attached from a "cle ip eigrp nei" and a packet that is not from the same router.

Kindest regards,

Ken

4 REPLIES
Anonymous
N/A

Re: EIGRP Flag 0x9 (What is it)

Is the o/p u have given is a bug o/p?.I mean is this the normal operational debug or faulty operational.Any how, I think the flag 0x9 is set and seen on the device, when some sort of link flapping b/w the 2 eigrp neighbors occurs.Since it comes after clear ip eigrp neighbors command, I think it is trying to initialise and establish new neighbor relationship.

New Member

Re: EIGRP Flag 0x9 (What is it)

Hi there :) Thx for the reply.

The output is just normal operation and is not service affecting in any way.

It was just I was looking at the neighbor establishment process for eigrp and saw that certain flags are set at certain times.

It, INIT flag on session startup and C/R flag on non responsive neighbors

Then saw 9 but could not find anything online to show what this could be?

Many thx

Ken

Gold

Re: EIGRP Flag 0x9 (What is it)

The flag field is a bitfield, rather than an integer, so multiple flags can be combined, in different situations. For instance, you know init is 0x1, and CR is 0x2. If, for some reason, you were going to init a neighbor, and tell them they are CR at the same time, you'd send 0x3 (0x1 + 0x2 == 0x3).

In this case, you're seeing 0x9, which is 0x8 + 0x1. 0x8 is end of table, and 0x1 is init. It seems like an odd combination (?), but it is what you are seeing.

HTH

Russ.W

New Member

Re: EIGRP Flag 0x9 (What is it)

Thx Mr W

As always you are very helpful.

And Thx to Mr P who replied :)

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