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eclipse-threadx
Impact of SLAAC on TCP UDP data flow
Hi,
As we understand that with SLAAC, IP address of DUT changes when the prefix in the RA changes, what will be the impact of this on ongoing TCP/UDP data flow? Will the data flow be interrupted? Secondly, can one interface have more than one valid state IP address at same time? meaning all usable for making individual connections? (1 Obtained by static/1 by dhcp/2 obtained by SLAAC all in nxd_ipv6_address_state = valid) as one interface maintains multiple ipv6 address array. Or only one should be valid in the array? Third, does netx stack support the clearing the state/sockets/connections of the SLAAC obtained IP address when the address is no more valid?
Thanks, Risha.
When an IPv6 address becomes invalid, a callback will be invoked which can be set by nxd_ipv6_address_change_notify. NetX will not delete or terminate TCP/UDP sockets. User application is responsible to handle TCP/UDP sockets. All sockets would be impacted except UDP client, which depends on the remote UDP server.
One IP interface only supports one IPv4 address. It can support multiple IPv6 addresses. See more details of this macro NX_MAX_IPV6_ADDRESSES.
"One IP interface only supports one IPv4 address. It can support multiple IPv6 addresses. See more details of this macro NX_MAX_IPV6_ADDRESSES" as quoted by you @TiejunMS I understand that one interface can support up to max 6 ipv6 addresses as defined by this macro, but can all of them or more than one of them be valid at the same time? i.e nxd_ipv6_address_state = NX_IPV6_ADDR_STATE_VALID for more than one ip address simultaneously?
That way we will have multiple connections on multiple ip address on same interface at the same time, multi homing kind, is that allowed ?
can all of them or more than one of them be valid at the same time?
Yes, they can. See example here.
Ok, so basically on one IP address if there is an ongoing TCP/UDP data download/upload going on, parallelly if SLAAC obtains a new IP and makes it valid, it should not interrupt the ongoing data flow rt?
For TCP socket, it will not be impacted after the connection is established. For UDP socket, since it is not connection based, it depends on the routing table. But you can use nxd_udp_socket_source_send to avoid source address change for UDP socket.