Technical data

5.2.1 Static Routing
Because static routing requires manual configuration, it is most useful when the
number of gateways is limited and when routes do not change frequently. For
information about manually configuring routing, refer to the Compaq TCP/IP
Services for OpenVMS Management guide.
5.2.2 Dynamic Routing
Complex environments require a more flexible approach to routing than a static
routing table provides. Routing protocols distribute information that reflect
changing network conditions and update the routing table accordingly. Routing
protocols can switch to a backup route when a primary route becomes unavailable,
and can determine the best route to a given destination.
Dynamic routing tables use information that is received by means of routing
protocol updates; when routes change, the routing protocol provides information
about the changes.
Routing daemons implement a routing policy, that is, a set of rules that specify
which routes go into the routing table. A routing daemon writes routing messages
to a routing socket, which causes the kernel to add a new route or delete , or
modify, an existing route.
The kernel also generates routing messages that can be read by any routing socket
when events occur that might be of interest to the process (for example, the
interface has gone down or a redirect has been received).
TCP/IP Services implements two routing daemons: the Routing Daemon
(ROUTED) and the Gateway Routing Daemon (GATED). The following
sections provide more information about these daemons.
RoutingDaemon(ROUTED)
The ROUTED daemon (pronounced “route-dee”) supports the Routing Information
Protocol (RIP). When ROUTED starts, it issues routing update requests and
then listens for responses. A system that is configured to supply RIP information
responds to the request with an update packet. The update packet contains
destination addresses and routing metrics associated with each destination. After
receiving a RIP update, the ROUTED uses the information to update its routing
table.
For details about how to configure dynamic routing with ROUTED, refer to the
Compaq TCP/IP Services for OpenVMS Management guide.
_________________________ Note _________________________
ROUTED supports Routing Information Protocol (RIP) V1 only.
ROUTED is considered older technology, and many system
administrators are replacing it with GATED.
Gateway Routing Daemon (GATED)
The GATED daemon (pronounced “gate-dee”) supports interior and exterior
gateway protocols. It obtains information from several routing protocols and selects
the best routes based on that information. You can configure GATED to use one or
more of the protocols described in Table 5–1.
5–4 Network Server Services