HP 3500YL - Manual (Page 218)

IP Routing Features
Configuring OSPF
Terminology
Area Border Router (ABR): An OSPF-enabled router having interfaces on
two or more OSPF areas. (Refer to “Area Border Routers (ABRs)” on
page 5-47.)
Autonomous System (AS): A single interior gateway protocol (IGP) domain
such as an OSPF or RIP domain.
Autonomous System Boundary Router (ASBR): An OSPF-enabled router
having interfaces in multiple IGP domains, such as an ASBR with member­
ship in both a normal area of an OSPF domain and a RIP domain. (Refer
to “Autonomous System Boundary Router (ASBR)” on page 5-48.)
Backbone Area: Required in any OSPF domain, this is the transit area for all
advertisements and routed traffic between non-backbone areas. (Refer to
“Backbone Area” on page 5-51.)
Backup Designated Router (BDR): If the DR for a network becomes
inaccessible, the BDR takes over the DR function. (See also “Designated
Router”, below, and refer to “Designated Routers” on page 5-48.)
Default Route: A route defined as 0.0.0.0/0. OSPF uses type 3 (summary)
defaults and type 7 (external) default routes.
Designated Router (DR): Used in networks having two or more routers,
and serves as the distribution point for forwarding updates throughout
the network. (See also “Backup Designated Router”, above, and refer to
“Designated Routers” on page 5-48.)
External Type-5 Link-State Advertisement: An LSA summarizing known
external links for the backbone and normal areas. Refer to Table 5-5 on
page 5-46. (See also “Link State Advertisement”.)
External Type-7 Link State Advertisement: An LSA originating with an
ASBR in an NSSA and allowed only in the NSSA. Refer to Table 5-5 on
page 5-46. (See also “Link State Advertisement”.)
Interior Gateway Protocol (IGP): A method for forwarding traffic between
autonomous routing domains. Commonly used between OSPF and RIP
domains.
Interior Router: An OSPF-enabled routing switch having interfaces in only
one OSPF area. (Refer to “Interior Routers” on page 5-47.)
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