OpenVMS Cluster Systems - OpenVMS Systems - HP

Troubleshooting the NISCA Protocol
F.7 Understanding NISCA Datagrams
Table F–9 Fields in the DX Header
Field Description
Destination SCS address Manufactured using the address AA–00–04–00–remote-node-
SCSSYSTEMID. Append the remote node’s SCSSYSTEMID
system parameter value for the low-order 16 bits. This address
represents the destination SCS transport address or the
OpenVMS Cluster multicast address.
Cluster group number The cluster group number specified by the system manager. See
Chapter 8 for more information about cluster group numbers.
Source SCS address Represents the source SCS transport address and is
manufactured using the address AA–00–04–00–local-node-
SCSSYSTEMID. Append the local node’s SCSSYSTEMID system
parameter value as the low-order 16 bits.
F.7.6 Channel Control (CC) Header
The channel control (CC) message is used to form and maintain working network
paths between nodes in the OpenVMS Cluster system. The important fields for
network troubleshooting are the datagram flags/type and the cluster password.
Note that because the CC and TR headers occupy the same space, there is
a TR/CC flag that identifies the type of message being transmitted over the
channel. Figure F–9 shows the portions of the CC header needed for network
troubleshooting, and Table F–10 describes these fields.
Figure F–9 CC Header
LAN
Header
DX
Header
F–22 Troubleshooting the NISCA Protocol
0
Datagram
Flags/Type
1 38 46
...
Cluster
Password
...
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