NIO CommKit Host Interface Installation and System Administration Manual

3-7

Control Tables (from AT&T 255-110-127)

Data Switch Dialstrings

• v and x are protocol values translated on the receiving (remote) end as:

v Environment variables should be read from the incoming data channel

x Open the remote execution protocol device driver for this channel.

The data switch node then adds routing information to the supplied dial-

string, and the receiving host sees the following dialstring arrive for service:

Chan.Token.Lflag.URPinit.Recbuf\n

nj/shore/hpams5x.rl.vx/n

104\n

Origin.Node.Mod.Ochan.Cflag[.Par1.Par2...}\n

Module Type Information\0

• Chan is the channel number assigned by the data switch node and subsequently

translated into a UNIX system device on the remote host

• nj/shore/hpams5x is the location provided by the caller on the local host in the

original dialstring

• rl is the service to be executed on the remote host (as supplied by the dk pro-

gram)

• v and x are the protocol values (as supplied by the dk program)

• 104 is the numerical user ID of the user goldfish on the calling fish

• Origin is the originating group

• Token, Lflag, Node, Mod, Ochan, Cflag, URPinit, and Recbuf are the keywords

associated with the values supplied by the data switch node.

The dkserver running on the remote host will process incoming call

requests. When the call comes in on the serving channel from the data

switch node, the server uses the incoming dialstring to interrogate the server

table to determine what action should be taken to satisfy this service request.

It uses the system (nj/shore/hpams5x), service (rl), and user (104) ﬁelds to

ﬁnd a match with an entry in srvtab so that the correct action can be taken.

The server table entry shown below matches the incoming call.

System Service Flags User Program Initial Parms

------------------------------------------------------------

nj/shore/* rl /vaex *n %s -Xsh:-c:%p

If protocol values of the ﬂags ﬁeld had not been supplied (which is not the

case in this example), then the protocol values v, a, e, and x would have been

supplied. The program executed on the remote host is %s, which is trans-

lated by dkserver into the pathname of the user’s shell as speciﬁed in the