Cisco Cisco ACE Application Control Engine Module Manual Técnica
Join Additional Sub−flows
When deemed necessary, Host−A might initiate additional sub−flows sourced from a different interface or
address to Host−B. As with the initial sub−flow, TCP options are used in order to indicate the desire to merge
this sub−flow with the other sub−flow. The keys that are exchanged within the initial sub−flow establishment
(along with a hashing algorithm) are used by Host−B in order to confirm that the join request is indeed sent
by Host−A. The secondary sub−flow 4−tuple (source IP, destination IP, source Port, and destination Port) is
different than that of the primary sub−flow; this flow might take a different path through the network.
address to Host−B. As with the initial sub−flow, TCP options are used in order to indicate the desire to merge
this sub−flow with the other sub−flow. The keys that are exchanged within the initial sub−flow establishment
(along with a hashing algorithm) are used by Host−B in order to confirm that the join request is indeed sent
by Host−A. The secondary sub−flow 4−tuple (source IP, destination IP, source Port, and destination Port) is
different than that of the primary sub−flow; this flow might take a different path through the network.
Add Address
Host−A has multiple interfaces, and it is possible that Host−B has multiple network connections. Host−B
learns about addresses A1 and A2 implicitly as a result of Host−A sourcing sub−flows from each of its
addresses destined to B1. It is possible that Host−B advertises its additional address (B2) to Host−A so that
other sub−flows are made to B2. This is completed via the TCP option 30. As shown in this diagram, Host−B
advertises its secondary address (B2) to Host−A, and two additional sub−flows are created. Because MPTCP
operates above the Network layer of the Open System Interconnection (OSI) stack, the IP addresses advertised
can be IPv4, IPv6, or both. It is possible that some of the sub−flows are transported by IPv4 simultaneously as
other sub−flows are transported by IPv6.
learns about addresses A1 and A2 implicitly as a result of Host−A sourcing sub−flows from each of its
addresses destined to B1. It is possible that Host−B advertises its additional address (B2) to Host−A so that
other sub−flows are made to B2. This is completed via the TCP option 30. As shown in this diagram, Host−B
advertises its secondary address (B2) to Host−A, and two additional sub−flows are created. Because MPTCP
operates above the Network layer of the Open System Interconnection (OSI) stack, the IP addresses advertised
can be IPv4, IPv6, or both. It is possible that some of the sub−flows are transported by IPv4 simultaneously as
other sub−flows are transported by IPv6.