HP-UX Reference (11i v1 00/12) - 4 File Formats (vol 8)
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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man4/!!!intro.4
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g
gated.conf(4) gated.conf(4)
Point-to-point interfaces also support this additionalparameter:
nomulticast
By default, OSPF packets to neighbors on point-to-point interfaces are sent via the IP
multicast mechanism. Although, some implementations of IP multicasting for Unix
have a bug that precludes the use of IP multicasting on these interfaces. Gated will
detect this condition and fall back to using sending unicast OSPF packets to this
point-to-point neighbor.
If the use of IP multicasting is not desired because the remote neighbor does not sup-
port it, the nomulticast parameter may be specified to force the use of unicast OSPF
packets. This option may also be used to eliminate warnings when Gated detects the
bug mentioned above.
interface interface_list nonbroadcast [cost cost ]
This form of the interface clause is used to specify a nonbroadcast interface on a non-
broadcast multi-access (NBMA) media. Since an OSPF broadcast media must support IP
multicasting, a broadcast capable media, such as Ethernet, that does not support IP multicasting
must be configured as a non-broadcast interface.
A non-broadcast interface supports any of the standard interface clauses listed above, plus
the following two that are specific to non-broadcast interfaces:
pollinterval time
Before adjacency is established with a neighbor, OSPF packets are sent periodically at
the specified pollinterval.
routers
By definition it is not possible to send broadcast packets to discover OSPF neighbors
on a non-broadcast, so all neighbors must be configured. The list includes one or more
neighbors and an indicationof their eligibility to become a designated router.
virtuallink neighborid router_id transitarea area
Virtual links are used to establish or increase connectivity of the backbone area. The neigh-
borid is the router_id of the other end of the virtual link. The transit area specified must also
configured on this system. All standard interface parameters defined by the interface clause
above may be specified on a virtual link.
Tracing options
In addition to the following OSPF specific trace flags, OSPF supports the state which traces interface and
neighbor state machine transitions.
lsabuild
Link State Advertisement creation
spf Shortest Path First (SPF) calculations
Packet tracing options (which may be modified with detail, send and recv):
hello
OSPF HELLO packets which are used to determine neighbor reachability.
dd OSPF Database Description packets which are used in synchronizing OSPF databases.
request
OSPF Link State Request packets which are used in synchronizing OSPF databases.
lsu OSPF Link State Update packets which are used in synchronizing OSPF databases.
ack OSPF Link State Ack packets which are used in synchronizing OSPF databases.
The Exterior Gateway Protocol (EGP)
The Exterior Gateway Protocol (EGP) is an exterior routing protocol used for exchanging routing informa-
tion with gateways in other autonomous systems. Unlike interior protocols, EGP propagates only reachabil-
ity indications, not true metrics. EGP updates contain metrics, called distances which range from 0 to 255.
GateD will only compare EGP distances learned from the same AS. them.
Before EGP sends routing information to a remote router, it must establish an adjacency with that router.
This is accomplished by an exchange of Hello (not to be confused with the HELLO protocol, or OSPF
HELLO messages) and I Heard You (I-H-U) messages with that router. Computers communicating via
HP-UX Release 11i: December 2000 − 22 − Section 4−−93
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