The indication of whether this entity is acting as an IP
router in respect to the forwarding of datagrams received
by, but not addressed to, this entity. IP routers forward
datagrams. IP hosts do not (except those source-routed via
The number of input datagrams discarded due to errors in
their IP headers, including bad checksums, version number
mismatch, other format errors, time-to-live exceeded, errors
discovered in processing their IP options, etc.
The number of input datagrams discarded because the IP
address in their IP header's destination field was not a
valid address to be received at this entity. This count
includes invalid addresses (e.g., 0.0.0.0) and addresses of
unsupported Classes (e.g., Class E). For entities which are
not IP routers and therefore do not forward datagrams, this
counter includes datagrams discarded because the destination
address was not a local address.
The number of input datagrams for which this entity was not
their final IP destination, as a result of which an attempt
was made to find a route to forward them to that final
destination. In entities which do not act as IP routers,
this counter will include only those packets which were
Source-Routed via this entity, and the Source-Route option
processing was successful.
The number of input IP datagrams for which no problems were
encountered to prevent their continued processing, but which
were discarded (e.g., for lack of buffer space). Note that
this counter does not include any datagrams discarded while
The total number of IP datagrams which local IP user-
protocols (including ICMP) supplied to IP in requests for
transmission. Note that this counter does not include any
datagrams counted in ipForwDatagrams.
The number of output IP datagrams for which no problem was
encountered to prevent their transmission to their
destination, but which were discarded (e.g., for lack of
buffer space). Note that this counter would include
datagrams counted in ipForwDatagrams if any such packets met
this (discretionary) discard criterion.
The number of IP datagrams discarded because no route could
be found to transmit them to their destination. Note that
this counter includes any packets counted in ipForwDatagrams
which meet this `no-route' criterion. Note that this
includes any datagrams which a host cannot route because all
of its default routers are down.
The number of failures detected by the IP re-assembly
algorithm (for whatever reason: timed out, errors, etc).
Note that this is not necessarily a count of discarded IP
fragments since some algorithms (notably the algorithm in
RFC 815) can lose track of the number of fragments by
combining them as they are received.
The number of ICMP messages which this entity did not send
due to problems discovered within ICMP such as a lack of
buffers. This value should not include errors discovered
outside the ICMP layer such as the inability of IP to route
the resultant datagram. In some implementations there may
be no types of error which contribute to this counter's