
Nortel Switched Firewall 2.3.3 User’s Guide and Command Reference
Open Shortest Path First
97
213455-L, October 2005
Transit Area—an area that allows area summary information to be exchanged between
routing devices. The backbone (area 0) and any area that is not a stub area or an NSSA are
considered transit areas (see
Figure 53
).
Figure 53
OSPF area types
Types of OSPF routing devices
As shown in
Figure 53
, OSPF uses the following types of routing devices:
Internal Router (IR)—a router that has all of its interfaces within the same area. IRs
maintain LSDBs identical to those of other routing devices within the local area.
Area Border Router (ABR)—a router that has interfaces in multiple areas. ABRs maintain
one LSDB for each connected area and disseminate routing information between areas.
Backbone
Area 0
Stub Area
Not-So-Stubby Area
(NSSA)
Transit Area
No External Routes
from Backbone
Stub Area, NSSA,
or Transit Area
Connected to Backbone
via Virtual Link
(Also a Transit Area)
External LSA
Routes
Internal LSA
Routes
ABR
ABR
ABR
ASBR
Non-OSPF Area
RIP/BGP AS
Virtual
Link
ABR
ABR
= Area Border Router
ASBR = Autonomous System
Boundary Router
Содержание 5100 Series Release 2.3.3
Страница 18: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 18 Preface 213455 L October 2005...
Страница 20: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 20 Getting started 213455 L October 2005...
Страница 28: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 28 Introduction 213455 L October 2005...
Страница 90: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 90 Initial setup 213455 L October 2005...
Страница 188: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 188 Redundant Firewalls 213455 L October 2005...
Страница 228: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 228 Applications 213455 L October 2005...
Страница 248: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 248 Basic system management 213455 L October 2005...
Страница 250: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 250 Command reference 213455 L October 2005...
Страница 264: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 264 The Command Line Interface 213455 L October 2005...
Страница 374: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 374 Command reference 213455 L October 2005...
Страница 376: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 376 Appendices 213455 L October 2005...
Страница 406: ...Nortel Switched Firewall 2 3 3 User s Guide and Command Reference 406 Common tasks 213455 L October 2005...