Viewing IP Group Statistics
5-4
No Route The number of IP datagrams discarded because no route
could be found to transmit them to their destination. This
counter includes packets counted in ipForwDatagrams
which meet this ‘no-route’ criterion, and any datagrams a
host cannot route because all of its default gateways are
down. This field displays the ipOutNoRoutes.
Datagram Fragmentation
Datagrams The number of IP datagrams that have been successfully
Fragmented fragmented at this entity, according to the ipFragOKs. A
station fragments a datagram if the datagram is too large
to fit within a physical frame.
Discarded The number of IP datagrams that have been discarded
because they needed to be fragmented at this entity but
could not be (e.g., because their Don’t Fragment flag was
set). This field displays the ipFragFails.
Fragments Created The number of IP datagram fragments that have been
generated as a result of fragmentation at this entity,
according to the ipFragCreate.
Datagram Reassembly
Fragments Recvd The number of IP fragments received which needed to be
reassembled at this entity, according to the ipReasmReqds.
Datagrams The number of IP datagrams successfully reassembled,
Reassembled according to the ipReasmOKs. If a datagram is
fragmented for transmission, the receiving station is
responsible for reassembling the fragments. If the
receiving station receives all fragments within the time
period specified by the reassembly timer, it increments
the Reasm OKs timer.
Reassembly Failures The number of failures detected by th e IP reassembly
algorithm. 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. This
field displays the ipReasmFails.
Reassembly TimeOut The maximum number of seconds which received
fragments are held while they are awaiting reassembly at
this entity, according to the ipReasmTimeout. IP attempts
to encapsulate each datagram in a single physical frame.
If it cannot do so, it fragments the datagram into multiple
physical frames, The receiving station starts a reassembly
timer when it receives the first fragment. If the timer
expires before all fragments arrive, the device discards
the fragments already received. The reassembly timer is a
read-only attribute.