Connected: An Internet Encyclopedia
6.6. The IP Group

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6.6. The IP Group

6.6. The IP Group

          -- the IP group

          -- Implementation of the IP group is mandatory for all
          -- systems.

          ipForwarding OBJECT-TYPE
              SYNTAX  INTEGER {
                          forwarding(1),    -- acting as a gateway
                          not-forwarding(2) -- NOT acting as a gateway
                      }
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The indication of whether this entity is acting
                      as an IP gateway in respect to the forwarding of
                      datagrams received by, but not addressed to, this
                      entity.  IP gateways forward datagrams.  IP hosts
                      do not (except those source-routed via the host).

                      Note that for some managed nodes, this object may
                      take on only a subset of the values possible.
                      Accordingly, it is appropriate for an agent to
                      return a `badValue' response if a management
                      station attempts to change this object to an
                      inappropriate value."
              ::= { ip 1 }

          ipDefaultTTL OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The default value inserted into the Time-To-Live
                      field of the IP header of datagrams originated at
                      this entity, whenever a TTL value is not supplied
                      by the transport layer protocol."
              ::= { ip 2 }

          ipInReceives OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The total number of input datagrams received from
                      interfaces, including those received in error."
              ::= { ip 3 }

          ipInHdrErrors OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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."
              ::= { ip 4 }

          ipInAddrErrors OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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 Gateways and therefore do not
                      forward datagrams, this counter includes datagrams
                      discarded because the destination address was not
                      a local address."
              ::= { ip 5 }

          ipForwDatagrams OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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 Gateways, this
                      counter will include only those packets which were
                      Source-Routed via this entity, and the Source-
                      Route option processing was successful."
              ::= { ip 6 }

          ipInUnknownProtos OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of locally-addressed datagrams
                      received successfully but discarded because of an
                      unknown or unsupported protocol."
              ::= { ip 7 }

          ipInDiscards OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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 awaiting re-assembly."
              ::= { ip 8 }

          ipInDelivers OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The total number of input datagrams successfully
                      delivered to IP user-protocols (including ICMP)."
              ::= { ip 9 }

          ipOutRequests OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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."
              ::= { ip 10 }

          ipOutDiscards OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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."
              ::= { ip 11 }

          ipOutNoRoutes OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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
                      datagarms which a host cannot route because all of
                      its default gateways are down."
              ::= { ip 12 }

          ipReasmTimeout OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The maximum number of seconds which received
                      fragments are held while they are awaiting
                      reassembly at this entity."
              ::= { ip 13 }

          ipReasmReqds OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of IP fragments received which needed
                      to be reassembled at this entity."
              ::= { ip 14 }

          ipReasmOKs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of IP datagrams successfully re-
                      assembled."
              ::= { ip 15 }

          ipReasmFails OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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."
              ::= { ip 16 }

          ipFragOKs OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of IP datagrams that have been
                      successfully fragmented at this entity."
              ::= { ip 17 }

          ipFragFails OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "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."
              ::= { ip 18 }

          ipFragCreates OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of IP datagram fragments that have
                      been generated as a result of fragmentation at
                      this entity."
              ::= { ip 19 }

          -- the IP address table

          -- The IP address table contains this entity's IP addressing
          -- information.

          ipAddrTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF IpAddrEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "The table of addressing information relevant to
                      this entity's IP addresses."
              ::= { ip 20 }

          ipAddrEntry OBJECT-TYPE
              SYNTAX  IpAddrEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "The addressing information for one of this
                      entity's IP addresses."
              INDEX   { ipAdEntAddr }
              ::= { ipAddrTable 1 }

          IpAddrEntry ::=
              SEQUENCE {
                  ipAdEntAddr
                      IpAddress,
                  ipAdEntIfIndex
                      INTEGER,
                  ipAdEntNetMask
                      IpAddress,
                  ipAdEntBcastAddr
                      INTEGER,
                  ipAdEntReasmMaxSize
                      INTEGER (0..65535)
              }

          ipAdEntAddr OBJECT-TYPE
              SYNTAX  IpAddress
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The IP address to which this entry's addressing
                      information pertains."
              ::= { ipAddrEntry 1 }

          ipAdEntIfIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The index value which uniquely identifies the
                      interface to which this entry is applicable.  The
                      interface identified by a particular value of this
                      index is the same interface as identified by the
                      same value of ifIndex."
              ::= { ipAddrEntry 2 }

          ipAdEntNetMask OBJECT-TYPE
              SYNTAX  IpAddress
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The subnet mask associated with the IP address of
                      this entry.  The value of the mask is an IP
                      address with all the network bits set to 1 and all
                      the hosts bits set to 0."
              ::= { ipAddrEntry 3 }

          ipAdEntBcastAddr OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The value of the least-significant bit in the IP
                      broadcast address used for sending datagrams on
                      the (logical) interface associated with the IP
                      address of this entry.  For example, when the
                      Internet standard all-ones broadcast address is
                      used, the value will be 1.  This value applies to
                      both the subnet and network broadcasts addresses
                      used by the entity on this (logical) interface."
              ::= { ipAddrEntry 4 }

          ipAdEntReasmMaxSize OBJECT-TYPE
              SYNTAX  INTEGER (0..65535)
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The size of the largest IP datagram which this
                      entity can re-assemble from incoming IP fragmented
                      datagrams received on this interface."
              ::= { ipAddrEntry 5 }

          -- the IP routing table

          -- The IP routing table contains an entry for each route
          -- presently known to this entity.

          ipRouteTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF IpRouteEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "This entity's IP Routing table."
              ::= { ip 21 }

          ipRouteEntry OBJECT-TYPE
              SYNTAX  IpRouteEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "A route to a particular destination."
              INDEX   { ipRouteDest }
              ::= { ipRouteTable 1 }

          IpRouteEntry ::=
              SEQUENCE {
                  ipRouteDest
                      IpAddress,
                  ipRouteIfIndex
                      INTEGER,
                  ipRouteMetric1
                      INTEGER,
                  ipRouteMetric2
                      INTEGER,
                  ipRouteMetric3
                      INTEGER,
                  ipRouteMetric4
                      INTEGER,
                  ipRouteNextHop
                      IpAddress,
                  ipRouteType
                      INTEGER,
                  ipRouteProto
                      INTEGER,
                  ipRouteAge
                      INTEGER,
                  ipRouteMask
                      IpAddress,
                  ipRouteMetric5
                      INTEGER,
                  ipRouteInfo
                      OBJECT IDENTIFIER
              }

          ipRouteDest OBJECT-TYPE
              SYNTAX  IpAddress
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The destination IP address of this route.  An
                      entry with a value of 0.0.0.0 is considered a
                      default route.  Multiple routes to a single
                      destination can appear in the table, but access to
                      such multiple entries is dependent on the table-
                      access mechanisms defined by the network
                      management protocol in use."
              ::= { ipRouteEntry 1 }

          ipRouteIfIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The index value which uniquely identifies the
                      local interface through which the next hop of this
                      route should be reached.  The interface identified
                      by a particular value of this index is the same
                      interface as identified by the same value of
                      ifIndex."
              ::= { ipRouteEntry 2 }

          ipRouteMetric1 OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The primary routing metric for this route.  The
                      semantics of this metric are determined by the
                      routing-protocol specified in the route's
                      ipRouteProto value.  If this metric is not used,
                      its value should be set to -1."
              ::= { ipRouteEntry 3 }

          ipRouteMetric2 OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "An alternate routing metric for this route.  The
                      semantics of this metric are determined by the
                      routing-protocol specified in the route's
                      ipRouteProto value.  If this metric is not used,
                      its value should be set to -1."
              ::= { ipRouteEntry 4 }

          ipRouteMetric3 OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "An alternate routing metric for this route.  The
                      semantics of this metric are determined by the
                      routing-protocol specified in the route's
                      ipRouteProto value.  If this metric is not used,
                      its value should be set to -1."
              ::= { ipRouteEntry 5 }

          ipRouteMetric4 OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "An alternate routing metric for this route.  The
                      semantics of this metric are determined by the
                      routing-protocol specified in the route's
                      ipRouteProto value.  If this metric is not used,
                      its value should be set to -1."
              ::= { ipRouteEntry 6 }

          ipRouteNextHop OBJECT-TYPE
              SYNTAX  IpAddress
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The IP address of the next hop of this route.
                      (In the case of a route bound to an interface
                      which is realized via a broadcast media, the value
                      of this field is the agent's IP address on that
                      interface.)"
              ::= { ipRouteEntry 7 }

          ipRouteType OBJECT-TYPE
              SYNTAX  INTEGER {
                          other(1),        -- none of the following

                          invalid(2),      -- an invalidated route
                                           -- route to directly
                          direct(3),       -- connected (sub-)network

                                           -- route to a non-local
                          indirect(4)      -- host/network/sub-network
                      }
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The type of route.  Note that the values
                      direct(3) and indirect(4) refer to the notion of
                      direct and indirect routing in the IP
                      architecture.

                      Setting this object to the value invalid(2) has
                      the effect of invalidating the corresponding entry
                      in the ipRouteTable object.  That is, it
                      effectively dissasociates the destination
                      identified with said entry from the route
                      identified with said entry.  It is an
                      implementation-specific matter as to whether the
                      agent removes an invalidated entry from the table.
                      Accordingly, management stations must be prepared
                      to receive tabular information from agents that
                      corresponds to entries not currently in use.
                      Proper interpretation of such entries requires
                      examination of the relevant ipRouteType object."
              ::= { ipRouteEntry 8 }

          ipRouteProto OBJECT-TYPE
              SYNTAX  INTEGER {
                          other(1),       -- none of the following

                                          -- non-protocol information,
                                          -- e.g., manually configured
                          local(2),       -- entries

                                          -- set via a network
                          netmgmt(3),     -- management protocol

                                          -- obtained via ICMP,
                          icmp(4),        -- e.g., Redirect

                                          -- the remaining values are
                                          -- all gateway routing
                                          -- protocols
                          egp(5),
                          ggp(6),
                          hello(7),
                          rip(8),
                          is-is(9),
                          es-is(10),
                          ciscoIgrp(11),
                          bbnSpfIgp(12),
                          ospf(13),
                          bgp(14)
                      }
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The routing mechanism via which this route was
                      learned.  Inclusion of values for gateway routing
                      protocols is not intended to imply that hosts
                      should support those protocols."
              ::= { ipRouteEntry 9 }

          ipRouteAge OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The number of seconds since this route was last
                      updated or otherwise determined to be correct.
                      Note that no semantics of `too old' can be implied
                      except through knowledge of the routing protocol
                      by which the route was learned."
              ::= { ipRouteEntry 10 }

          ipRouteMask OBJECT-TYPE
              SYNTAX  IpAddress
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "Indicate the mask to be logical-ANDed with the
                      destination address before being compared to the
                      value in the ipRouteDest field.  For those systems
                      that do not support arbitrary subnet masks, an
                      agent constructs the value of the ipRouteMask by
                      determining whether the value of the correspondent
                      ipRouteDest field belong to a class-A, B, or C
                      network, and then using one of:

                           mask           network
                           255.0.0.0      class-A
                           255.255.0.0    class-B
                           255.255.255.0  class-C
                      If the value of the ipRouteDest is 0.0.0.0 (a
                      default route), then the mask value is also
                      0.0.0.0.  It should be noted that all IP routing
                      subsystems implicitly use this mechanism."
              ::= { ipRouteEntry 11 }

          ipRouteMetric5 OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "An alternate routing metric for this route.  The
                      semantics of this metric are determined by the
                      routing-protocol specified in the route's
                      ipRouteProto value.  If this metric is not used,
                      its value should be set to -1."
              ::= { ipRouteEntry 12 }

          ipRouteInfo OBJECT-TYPE
              SYNTAX  OBJECT IDENTIFIER
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "A reference to MIB definitions specific to the
                      particular routing protocol which is responsible
                      for this route, as determined by the value
                      specified in the route's ipRouteProto value.  If
                      this information is not present, its value should
                      be set to the OBJECT IDENTIFIER { 0 0 }, which is
                      a syntatically valid object identifier, and any
                      conformant implementation of ASN.1 and BER must be
                      able to generate and recognize this value."
              ::= { ipRouteEntry 13 }

          -- the IP Address Translation table

          -- The IP address translation table contain the IpAddress to
          -- `physical' address equivalences.  Some interfaces do not
          -- use translation tables for determining address
          -- equivalences (e.g., DDN-X.25 has an algorithmic method);
          -- if all interfaces are of this type, then the Address
          -- Translation table is empty, i.e., has zero entries.

          ipNetToMediaTable OBJECT-TYPE
              SYNTAX  SEQUENCE OF IpNetToMediaEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "The IP Address Translation table used for mapping
                      from IP addresses to physical addresses."
              ::= { ip 22 }

          ipNetToMediaEntry OBJECT-TYPE
              SYNTAX  IpNetToMediaEntry
              ACCESS  not-accessible
              STATUS  mandatory
              DESCRIPTION
                      "Each entry contains one IpAddress to `physical'
                      address equivalence."
              INDEX   { ipNetToMediaIfIndex,
                        ipNetToMediaNetAddress }
              ::= { ipNetToMediaTable 1 }

          IpNetToMediaEntry ::=
              SEQUENCE {
                  ipNetToMediaIfIndex
                      INTEGER,
                  ipNetToMediaPhysAddress
                      PhysAddress,
                  ipNetToMediaNetAddress
                      IpAddress,
                  ipNetToMediaType
                      INTEGER
              }

          ipNetToMediaIfIndex OBJECT-TYPE
              SYNTAX  INTEGER
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The interface on which this entry's equivalence
                      is effective.  The interface identified by a
                      particular value of this index is the same
                      interface as identified by the same value of
                      ifIndex."
              ::= { ipNetToMediaEntry 1 }

          ipNetToMediaPhysAddress OBJECT-TYPE
              SYNTAX  PhysAddress
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The media-dependent `physical' address."
              ::= { ipNetToMediaEntry 2 }

          ipNetToMediaNetAddress OBJECT-TYPE
              SYNTAX  IpAddress
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The IpAddress corresponding to the media-
                      dependent `physical' address."
              ::= { ipNetToMediaEntry 3 }

          ipNetToMediaType OBJECT-TYPE
              SYNTAX  INTEGER {
                          other(1),        -- none of the following
                          invalid(2),      -- an invalidated mapping
                          dynamic(3),
                          static(4)
                      }
              ACCESS  read-write
              STATUS  mandatory
              DESCRIPTION
                      "The type of mapping.

                      Setting this object to the value invalid(2) has
                      the effect of invalidating the corresponding entry
                      in the ipNetToMediaTable.  That is, it effectively
                      dissasociates the interface identified with said
                      entry from the mapping identified with said entry.
                      It is an implementation-specific matter as to
                      whether the agent removes an invalidated entry
                      from the table.  Accordingly, management stations
                      must be prepared to receive tabular information
                      from agents that corresponds to entries not
                      currently in use.  Proper interpretation of such
                      entries requires examination of the relevant
                      ipNetToMediaType object."
              ::= { ipNetToMediaEntry 4 }

          -- additional IP objects

          ipRoutingDiscards OBJECT-TYPE
              SYNTAX  Counter
              ACCESS  read-only
              STATUS  mandatory
              DESCRIPTION
                      "The number of routing entries which were chosen
                      to be discarded even though they are valid.  One
                      possible reason for discarding such an entry could
                      be to free-up buffer space for other routing
                      entries."
              ::= { ip 23 }


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6.6. The IP Group