1 - 2 - 3 - 6 - 8 - A - B - C - D - E - F - G - H - I - J - L - M - N - O - P - Q - R - S - T - U - V - W - X
OSPF router
Click on the red underlined text to get to the source
... All OSPF implementations must be capable of calculating routes based on
TOS. However, OSPF routers can be configured to route all packets on
the TOS ...
...
Before the introduction of areas, the only OSPF routers having a
specialized function were those advertising external routing
information, such as router ...
... Type of Service. However, to save routing table space
and processing resources, an OSPF router can be configured to ignore
TOS when forwarding packets ...
...
An OSPF router converses with its neighboring routers. Each separate
conversation is described by a "neighbor ...
... neighbor data structure". Each
conversation is bound to a particular OSPF router interface, and is
identified either by the neighboring router ...
... interface, and is
identified either by the neighboring router's OSPF router ID or by its
Neighbor IP address (see below). Thus if the ...
... ID or by its
Neighbor IP address (see below). Thus if the OSPF router and another
router have multiple attached networks in common, multiple conversations
...
...
When an IP data packet is received, an OSPF router finds the routing
table entry that best matches the packet's destination. This routing
table ...
... Designated Router; each fully
adjacent router is identified by its OSPF Router ID. The Designated
Router includes itself in this list.
...
... 0.0.0.0, indicating that packets for the external destination should be
forwarded to the advertising OSPF router (RT7). This is not always
desirable. Consider the example pictured in Figure 16. There are three
OSPF routers (RTA, RTB and RTC) connected to a common ...
... forwarded to the advertising OSPF router (RT7). This is not always
desirable. Consider the example pictured in Figure 16. There are three
OSPF routers (RTA, RTB and RTC) connected to a common network. Only one
of these routers ...
... of these routers, RTA, is exchanging EGP information with the non-OSPF
router RTX. RTA must then originate AS external link state
advertisements for those destinations ...
... forwarding address), then the advertisement originated by the
router having the highest OSPF Router ID is used. The router having the
lower OSPF Router ...
... OSPF Router ID is used. The router having the
lower OSPF Router ID can then flush its advertisement. Flushing a link
state advertisement is discussed in Section 14.1.
...
... . These are the link state advertisements having the
router's own OSPF Router ID in the Advertising Router field.
...
... Link ID
set to the virtual neighbor's OSPF Router ID and Link Data set to
the virtual interface ...
... 32-bit number uniquely identifying the vertex. For router
vertices this is the OSPF Router ID. For network vertices, this is
the IP address ...
... router that does not support TOS indicates this fact to the
other OSPF routers by clearing the T-bit in the Options field of its
...
... address space of IP networks and the address space of OSPF Router IDs may overlap. That is, a network may have an IP address which is identical (when considered as a 32-bit number ...
... Database
Description packets and all link state advertisements. The options
field enables OSPF routers to support (or not support) optional
capabilities, and to communicate their capability level to other OSPF
routers. Through this mechanism routers ...
... options
field enables OSPF routers to support (or not support) optional
capabilities, and to communicate their capability level to other OSPF
routers. Through this mechanism routers of differing capabilities can
be mixed within an OSPF ...
... advertisements, the Link State ID field is set to the
router's OSPF Router ID. The T-bit is set in the advertisement's Option
field if and only if the router ...
... ID field is the AS boundary
router's OSPF Router ID. (To see why it is necessary to advertise the
location of each ASBR, consult Section 16.4.) Other than the difference
...
... In version 1 of the OSPF specification, all OSPF routers were required
to route based on TOS ...
... packets should be forwarded through the advertising router. However,
consider the situation where multiple OSPF routers share a LAN with an
external router ...
... external router (call it router Y) , and only one OSPF router (call it
router X) exchanges routing information with Y. The ...
... (call it
router X) exchanges routing information with Y. The OSPF routers on the
LAN other than X will forward packets destined for Y and beyond through
X, generating an extra hop (see Section 2.2).
...
... routers (X and Z)
exchanging EGP information with the non-OSPF router Y. It is then
likely that both X and Z will originate the same set of external routes.
Two AS ...
... . These are the link state advertisements having the
router's own OSPF router ID in the Advertising Router field.
...