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This appendix describes the implementation guidelines for monitoring FDDI, WAN, and ATM traffic.
SwitchProbe devices are designed to interoperate with networks management applications. Although there is no RMON standard for FDDI, WAN and ATM, Cisco Systems has extended the standard for these topologies so these extensions are usable and exercisable by as many third-party applications as possible.
Table A-1 describes Cisco Systems' implementation guidelines for monitoring FDDI traffic using RMON RFC 1757. The agent uses the Ethernet MIB without modification, except for UnderSize, Oversize, Collisions, Fragments, and Jabbers, which are modified slightly for FDDI-specific conditions.
| Ethernet MIB Variable | FDDI MIB Variable | Explanation |
|---|---|---|
Undersize | <64 | Packets less than 64 bytes in length. |
Oversize | >1518 | Packets greater than 1518 bytes in length. |
Collisions | TokenPkts | Number of Token Ring packets. |
Fragments | SMTPkts | Number of SMT packets. |
Jabbers | - | Reserved. |
Unlike Ethernet, FDDI is based on a ring topology similar to Token Ring. To implement the FDDI Ring Monitor application, Token Ring RMON MIB (RFC 1513) groups have been used as follows:
| Token Ring MIB Variable Name | FDDI MIB Variable Name | Modification |
|---|---|---|
ringStationDuplicateAddresses | Node Class | Indicates FDDI node type: |
ringStationInLineErrors | MAC Count | Counts MACs within the node. |
ringStationOutLineErrors | Non-Master Count | Indicates number of Non-Master ports in a concentrator-type FDDI node. Valid only if Node Class is 1 (Concentrator). |
ringStationInternalErrors | Master Count | Indicates number of Master ports in a concentrator-type FDDI node. Valid only if Node Class is 1 (Concentrator). |
ringStationInBurstErrors | StationState | Bit-encoded variable to indicate state of FDDI node. The following bits are used:
|
ringStationOutBurstErrors | DuplicateAddressTest | Status of Duplicate Address test the FDDI node SMT performs.
|
| MIB Variable Name | Change |
|---|---|
ringStationACEErrors | Unused |
ringStationLostFrameErrors | Unused |
ringStationCongestionErrors | Unused |
ringStationFrameCopiedErrors | Unused |
ringStationFrequencyErrors | Unused |
ringStationTokenErrors | Unused |
ringStationInBeaconErrors | Unused |
ringStationTokenOutBeaconErrors | Unused |
Table A-4 describes Cisco Systems' implementation guidelines for monitoring WAN traffic using RMON RFC 1757. The agent uses the Ethernet MIB with some modifications to account for WAN-specific conditions.
| Ethernet MIB Variable | WAN MIB Variable | Explanation |
|---|---|---|
CRCAlignErrors | CRCErrors | Name change only. |
UnderSize | LessThan64 | Name change only. |
OverSize | GreaterThan1518 | Name change only. |
Jabbers | Aborts | Sent by DTE or DCE; the number of abort sequences seen. |
Fragments | Discards | Number of frames sent to the Frame Relay switch with the discard eligibility (DE) bit set. |
Collisions | Congestions | Number of Frame Relay frames that have FECN or BECN bits set. Always 0 for other WAN connections. |
The process is as follows:
Step 1 The WAN header and trailer are removed.
Step 2 When the MAC header is missing, it is rebuilt using the DTE address of 0x7ee1000000 and DCE address of 0x7ee2000000 (pseudo-MAC header).
Step 3 The inOctets counter and the Utilization calculations use actual frame size, including the WAN header and trailer.
The following formula calculates utilization, given the octets and link_speed in bits per second:
utilization = ((octets*8 per second)/link_speed)*100
In the 32-bit RMON-MIB status word, the most significant bit (MSB) is clear for DTE-to-DCE frames and set for DCE-to-DTE frames.
The ATM SwitchProbe device assembles ATM cells into AAL5 protocol data units (PDUs). The device converts these PDUs into Ethernet-format frames to allow implementation of existing Remote Monitoring (RMON and RMON2) functionality. ATM-specific physical layer statistics (such as Cells, CallAttempts, and Calls) are mapped to certain etherStats objects in the Ethernet Statistics Group of the Ethernet RMON MIB (Table A-5). The resulting MIB is a "shadow" of the Ethernet RMON MIB.
Cells Total number of error-free cells detected. etherStatusUndersizePkts CallAttempts Number of call attempts detected on all signaled ATM connections. etherStatsJabbers Calls Number of successfully established calls detected on all signaled ATM connections. etherStatsFragments F5OAMCells Number of F5OAM (operations and maintenance) cells. etherStatsOversizePkts CRCErrors Cyclic redundancy check errors. The sum of AAL5 PDUs detected with CRC32 errors plus non-AAL5 cells detected with CRC10 errors. etherStatsCRCAlignErrors CLPCount Number of AAL5 PDUs detected with CLP1 bit set to 1. etherStatsCollisions
Table A-5: ATM Statistics Information Mapped to Ethernet RMON MIB
ATM MIB
Variable
Explanation
Mapped to (etherStats Object of Ethernet Statistics Group in Ethernet RMON MIB)
1CLP = Cell loss priority.
Posted: Wed Oct 2 08:31:29 PDT 2002
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