Detecting Network Attachment in
IPv6 Networks (DNAv6)
draft-ietf-dna-protocol-03.txt
S. Narayanan, Ed.
J. Kempf, E. Nordmark, B. Pentland,
JH. Choi, G. Daley,
N. Montavont, N. Moore.
Outline
•
•
•
•
Overview of the merge
Overview of DNA
Open Issues (AFAIK)
Proposed schedule
Overview of the merge
• Overview section (section 2)
– Expands to include
• Complete Prefix List
• Erroneous Prefix List
• Tentative Option (TO)
• New TLV format for TO
• No changes in DNA Router operation
• DNA Host operation
– DNA Steps from draft-ietf-dna-hosts
– Processing router advertisement
• Modified to include CPL for no link-change.
• Or wait for further RAs if the prefix list not complete.
Overview of the merge (Contd.)
• Just dropped in at the end
– Tentative option
– Initiation of DNA Procedures (from dna-host)
– Complication to DNA (from dna-host)
• Edited the document to
– Remove redundancy (Candidate Objects and
DNAHostPrefixList)
– Improve flow
– RA processing logic
DNA Steps
1. Try making use of prior information stored related to the links the host visited
in the past (see Section 5.2.4).
– If the prior information implies no link change, the host MAY conduct reachability
detection (see Section 5.2.7.4) to one of the default routers it is using, otherwise no
action is needed.
– If the prior information implies that there is a link change or there is no useful prior
information available, follow the procedure below.
2.
3.
4.
5.
6.
Mark all the IPv6 addresses in use as optimistic.
Set all Neighbor Cache entries for routers on its Default Router List to STALE.
Send router solicitation. (See Section 5.2.6).
Receive router advertisement (s).
Mark that router's Neighbor Cache Entry [3] as REACHABLE, or add a
Neighbor Cache Entry in the REACHABLE state if one does not currently
exist.
7. Process received router advertisement. (See Section 5.2.7).
8. If the link has changed Change the IP configuration parameters of the host (see
Section 5.2.8).
9. If the link has NOT changed Restore the address configuration state of all the
IPv6 addresses known to be on the link.
10.Update default routers list and their reachability information (see Section
5.2.7.4).
Processing RA
Receive RA
Yes
One of the received RA
contains a prefix matching a
prefix in
DNAHostPrefixList
from before link UP event
Received
RA contains a ‘Y’
Landmark that matches
the Landmark option in
the last
transmitted RS
No
Wait for NumRSRAComplete
exchanges of RS/RA message to
be done since
the previous link_up event
Yes
No
Received RA contains
LinkID AND LinkID
matches an entry in
DNAHostLinkIDList
Yes
No
No Link Change
DNAHostPrefixList is marked
as complete
(i.e. the completeness
criteria is already met)
No
Yes
Yes
Receive RA contains a
prefix matching a prefix
in DNAHostPrefixList
No
Yes
Yes
Link change
Receive RA is
a CompleteRA
No
No
Received RA contains
LinkID
AND
LinkID matches
none of the
entries in
DNAHostLinkIDList
Open Issues
1. WiMAX is trying to increase the MaxRtrAdvInterval into
hours or days. Should we change 1.5 hours to 3 *
MaxRtrAdvInterval?
2. What happens if no prefixes are advertised in a link? Is
such a scenario possible? Proposal is to mandate the AR to
advertise the linkID prefix.
3. Do we need Landmark Y/N bit?
• We never use the ‘N’ bit, because if the host has changed link, the
draft recommends sending a completeRA. It doesn’t make sense
to send a Landmark with N bit because it wastes space in the RA.
• ‘Y’ functionality can be achieved by just including the Landmark
prefix in the RA. But, the host will not know whether this RA is
in response to its request or not?
4. Should variables NumRSRAComplete, MinRAWait,
MaxCacheTime be kept as variables or should they be
constants?
Open Issues (Contd.)
4. DNA Terminology – Do we need any more terms
defined?
5. MaxCacheTime – Do we want to keep this
variable and its associated functionality?
6. Do we have to say something about storing old
LinkID list as prior information for future use?
•
There is some text w.r.t. old prefix list, I think? We
have to make this consistent.
Open Issues (Contd.)
8. Do we need a section on “DNA without
link UP notification”?
•
Current section with that title is text from
CPL. If we want to keep this, we need to
make it applicable for the whole scheme.
9. Do we want to keep “Initiation of DNA
procedures”?
10. Anything else?
Proposed schedule
• Next revision by ~ Dec 15
– Need substantial comments by Nov 30.
• Another revision by ~ Feb 15.
– Need substantial comments by Jan 31.