Zte ZXR10 GER - Figure 86 Ospf Router Type

ZXR10 GER (V2.6.03) General Excellent Router User Manual Volume-I
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OSPF router forms an adjacent relation with only DR and BDR. If
the DR stops work, the BDR will become a DR.
Each router interface has a priority, which will affect the router’s
capability of becoming a DR or BDR on the network to which
router is connected. A router priority is expressed with an eight-
bit unassigned integer, ranging from 0 to 255 (the default value
is "1").
Upon DR election, the router with highest priority will become
DR. If two routers have same priority, the one with the highest
IP address will become the DR. The router with priority "0"
cannot be DR or BDR.
OSPF areas divide a network into certain smaller parts to reduce
the information volume stored and maintained in each router.
Each router must have complete information about area where it
is located. The information among different areas is shared and
routing information can be filtered on edges of areas to reduce
routing information volume stored in router.
An area is identified with a 32-bit unsigned integer. Area 0 is
reserved and is used to indicate backbone network. The other
areas must be directly connected to area 0. An OSPF network
must have a backbone area. According to specific task in area
where a router is located, the router can be one or multiple
types of following routers, as shown in
Figure 86.
FIGURE 86 OSPF ROUTER TYPE
Area 1
ABR
RIP
ASBR
Area 2
Area 0
Internal router
Backbone router
Backbone router
Backbone router
 Internal router: Interfaces of the router are inside the same
area.
 Backbone router: At least one interface of the router is inside
area 0.
 Area Border Router (ABR): At least one interface of router is
inside area 0 and at least one interface is in other area.
 Autonomous System Border Router (ASBR): the router
connects an AS running OSPF to another AS running other
protocol (e.g. RIP .
LSA is a mode of exchanging link state database information
among OSPF routers. A router uses LSAs to construct an
Router Priority
and DR
Election
OSPF Area
Backbone Area
LSA Type and
Flooding