HP 200 Series Services And Applications page 179

A Primer on HP Probe
HP Probe Protocol Definition
over the secondary multicast address. See "Probe Proxy Request/Reply"
below for more information.
Node B responds to the name request with a path report that contains the IP
and link-level station (MAC) addresses of the target node. The station
address in the response received from the target node will only be consid-
ered valid if the IP or network numbers are the same as the originator's. If
they are not, then the originator must still resolve the IP-to-station-address
mapping. It does this with a Probe Virtual Address Request (VNA), as
described in the next section. If a proxy server replies to the request, it may
fill in the station address field with a null address or all zeros to ensure the
requester generates a VNA for the correct station address.
Probe Virtual Address Request/Reply - VNA
This is the equivalent to ARP in the NS world. It provides for the mapping of
a network (IP) address to link-level station address. The router will generate
a VNA when it needs to forward IP packets to an NS node and there is no
entry for it in its ARP cache. The router will have the destination IP address
and requires the station address in order to forward the packet. The target
node responds to the request with a path report that contains its station
address. The router then forwards the IP packet onto the destination NS
node. The router will respond to nodes generating these requests for
destination networks known to it.
Probe Proxy Request/Reply
The proxy request packet is basically the same as the name request
(see "Probe Name Request/Reply"), except that it is sent out over the
secondary multicast address. The secondary multicast address is listened to
only by Probe proxy nodes or servers. Proxy servers contain a database of
name-to-IP-address mappings for some or all of the nodes in the network.
The server will answer the requests for nodes that are on different subnets,
or for local nodes that cannot respond to name requests, with the IP address
from the database.
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