art@SAGE.ACC.COM (02/07/89)
Vint, Remember that level 2 does not really care about the ultimate destination, only the "next-hop" IP address (which could also be the destination). In most cases what X.25 needs to do is to translate the the IP address OF THE GATEWAY into an X.121 address. If an X.25 Call is received from a gateway (or host), one can translate from the Calling X.121 address to an IP address, so that the next time a packet needs to make that hop, it can use the same SVC. +-----------------------------------------------------------------------+ | Art Berggreen Advanced Computer Communications | | <art@sage.acc.com> Santa Barbara Street | | (805)963-9431 Santa Barbara, CA 93101 | +-----------------------------------------------------------------------+
CERF@A.ISI.EDU (02/09/89)
Art, Why struggle to translate from X.121 to IP if the arriving internet packet has a source IP address in it...oh, the source IP address isn't the address of the gateway, if there was a gateway, but the IP address of the source. Sorry, that's what I forgot. So you want a way to relay return traffic by way of the VC on which it was delivered. Seems to me that return traffic is going to get routed by the gateway based on the ultimate IP destination address of the returning traffic. If the IP address of the intermediate gateway can be mapped to an X.121 address, you could look for an existing X.25 VC with that destination X.121 address and put the packet on that - without having to map from X.121 to IP at any time, yes? Vint