draft-marushin-sctp-asconfext-01.txt

An extension to ADD-IP draft to send cumulativeASCONF chunks

draft-marushin-sctp-asconfext-01.txt

Shin Maruyama (Kyoto Univ., JAPAN)

Masahiro Kozuka (Kyoto Univ., JAPAN)

draft-marushin-sctp-asconfext-01.txt

Limitation on ASCONF transmission

• Sending new ASCONF chunk is prohibitedif outstanding ASCONF chunk exists.

• No modification on queued ASCONFs

draft-marushin-sctp-asconfext-01.txt

A typical scenario to break an association

• “Node A” supports IPv4 and IPv6 address• “Node B” supports only IPv4• “Node A” first loses IPv4 address and then get

another IPv4 address.Node A Node B

ASCONFDEL-IP(IPｖ４）

ASCONFADD-IP(IPｖ４）

Node A loses IPv4 address

Node A only has IPv6 address,ASCONF cannot be sent out

Once this happens, followingASCONFs are also blocked

IPv4

IPv6

IPv41.

2.

3.

draft-marushin-sctp-asconfext-01.txt

Another Typical Scenario• Node has a single interface and an IP

address, and the interface goes down.

• The node get another address, but the address is disconnected.

ASCONF

ASCONFADD-IP(IP３）

1.

2.

3.

IP1

ASCONF-ACK

IP1IP2

Node loses IP1

Get unreachable address IP2, ASCONF-ACK never returned

Get another reachable address IP3, but ASCONF cannot be sent out

draft-marushin-sctp-asconfext-01.txt

Cumulative ASCONF chunks

• On sending ASCONF chunks, if there are any outstanding ASCONFs, bind them up!

draft-marushin-sctp-asconfext-01.txt

Some Remarks• On bundling ASCONFs, all the outstanding ASCO

NFs must be bundled in order.

• ASCONF_ACK must be returned to the source address of bundled ASCONFs

• Receiver must return ASCONF_ACKs for all ASCONFS bundled even when some of themhave already processed.– ASCONF_ACK should be cached until the sender is ass

umed to have received it.

• ASCONF_ACK should also be bundled.

draft-marushin-sctp-asconfext-01.txt

Questions?

draft-marushin-sctp-asconfext-01.txt

BA

ASCONF 1,2

ASCONF 1,2,3,4,5

ACK 1,2

ASCONF 3,4,5

1,2

3,4,5

Retransmition

Ignored

Cache 1,2

Cache 3,4,5

ACK 3,4,5