Ahmad
I have a query
regarding the handling of Binding Revocation by MAG for individual binding
session.
Following is the
scenario:
Scenario:
1. Proxy Mobile
Initial Registration, MAG sends PBU to LMA with HNP option set to ALL_ZERO
for MN 1.
2. LMA in turn
sends back PBA with 3 HNP(s) assigned to MN 1 and updates Binding Cache
Entry.
3. MAG updates
Binding Update List entry and sends Router Advertisement to the MN with all
the
prefixes and prefix lifetime.
Note: MAG considers the prefix lifetime as binding
lifetime and starts Binding Lifetime timer.
4.
Bi-directional tunnel is established between MAG and LMA.
5. Prefix
Route(s) are created for all the prefixes at MAG.
6. MN 1 gets one
IP Address from the alloted 3 HNP(s).
7. LMA sends BRI
message with one HNP (out of the alloted 3 HNPs) with revoke trigger as
"ADMINISTRATIVE REASON".
After step 7,
when MAG receives BRI message with only one HNP and
MN-ID:
Queries:
1. Will MAG stop
the binding lifetime timer (started after binding session establishment),
due to the
received BRI message?
2. Will MAG
delete the complete Binding Update List maintained for the MN (MN 1) or will
it delete
only the corresponding HNP entry from the BUL and
send RA message to MN 1 (eventhough
the IP Address used by MN is not from the HNP
received in BRI message)? If it deletes only the
corresponding HNP entry, what will happen to the
Binding Lifetime timer?
[Ahmad]
If the LMA assigned 3 HNP
for MN1, then if the LMA would like to revoke all of the HNPs, the
LMA have one of the following
options:
1. Send BRI with MN-ID option
ONLY. This means that all HNPs are revoked, or
[Magesh] If there are multiple interfaces
(multi-homed) for the same MN, will MAG remove the Binding
Update List maintained for all the interfaces,
as there is no
Link
Layer Identifier Option in the BRI message?
[Ahmad]
The intention is to have this work sort of a
mini global revocation. In other words, if the LMA would like to revoke all
of the MN bindings, then including the MN-ID alone will suffice. I do not
see any problem in that and should be applicable to multihomed too. If the
LMA would like to revoke a single HNP, then LMA need to include the one
that needs to be
revoked.
2. Send a BRI with MN-ID and
all HNPs.
Although, the draft recommend
Number 1 BUT does not prevent No.
2.
On the other hand, if the LMA
sends a BRI with MN-ID and a single HNP, then the MAG MUST consider the
revocation of that single HNP and MUST NOT remove the MN1 from the
BUL.
[Magesh]
What will be the
status of binding lifetime timer?
Will the timer be
running even though the single HNP is removed from BUL entry (or will the
timer be stopped).
[Ahmad]
I probably need to clarify this one. If each
HNP maps to a separate binding, then that binding timer which is
defined by the included HNP should be cancelled. please see more
below.
[Magesh]
IMO, if LMA tries to
revoke a particular mobility session (Binding Cache Entry), it has to send
the MN-ID and all the
HNP(s) allocated for
the particular session. Sending of one HNP out of the allocated n HNP(s) should be
treated as Invalid Case.
The behavior should be same as PBU
received from MAG for De-Registration (where all
the
HNP(s) allocated are
present in the PBU message).
[Ahmad]
I guess we have two cases here. If the
BCE is allocated more than one HNP in the same PBU/PBA, then the LMA should
send BRI with MN-ID and no HNP(s) included to revoke the MN BCE. In this
specific case, if the LMA chooses to include the HNP option, the LMA SHOULD
include all of the allocated HNP(s). IMO, the LMA should include the MN-ID
ONLY and should suffice.
The other usecase, if the MN with multihoming
has multiple BCE(s) with different HNPs for each BCE. In this case, the
LMA MAY send a BRI to revoke a single BCE, e.g. with HNP=HNP1. In case the
LMA sends a BRI with MN-ID ONLY, i.e. without any HNP(s), the MAG should
handle this as if all of the MN BCE(s) have been revoked. In other words, if
the MN-ID has multiple BCE with different HNP(s), then the inclusion of the
HNP in the BRI is crucial for defining the MN BCE that is being
revoked.
I will make sure that the text in the draft is
clear on this.
Regards,
Ahmad
Hope this
help.
Regards,
Ahmad
Thanks
S
Magesh
