Trouble Shooting Guide
Table Of Contents
- Troubleshooting-Installing an RF link
- Issue : 5.3.x
- Authors : Matt Olson/Dave Sida
- Date : 30th July 2004
- CONTENTS
- CHANGE HISTORY
- INTRODUCTION
- Aligning an SU
- Fine tuning an SU
- SU signal quality
- Troubleshooting SU link from AP
- Link status
- AP Link Status
- SU Link Status
- MAC type
- Unit MAC address
- Channel
- Radio Channel Mask
- Correlation sequence
- MAC delay compensation
- Unit Range
- Base Station ID
- Radio Temperature
- RSSI
- Path loss in excess of FSL (estimate)
- Downlink RSSI Fade Margin
- TX maximum backoff
- TX current backoff
- Max TX power for channel
- Actual TX power
- Averaging MAC error rates over
- Downlink Header Error Rate
- Downlink Cell Error Rate
- Uplink Cell Error Rate
- Modem RSSI
- Mac stats
- Modem txpower
- Modem mmse
- PNMS Sector
- Survey Scan
- Modem msreg 6 1
- Modem rxdc stats
- Bun list channels
Axxcelera Broadband
Troubleshooting-Installing an RF link - 24 - Issue: 5.3.x
Rev 2
9 Mac stats
The MAC stats show the RF-link statistics. It is one of the primary tool for diagnosing RF-
problems. The “hmm link status” command reports some error rates based on the MAC
stats, but these are sampled over a very short period of time, and only show the
performance at that instant. In contrast, the “hmm mac stats” command can be used to
look at average error rates over any period of time. Between them the MAC stats and the
Modem RxDC stats (see section 15) will show the presence of either intermittent or
permanent RF problems, and will give an indication of the likely causes. Other
commands may then be required to pin-point the exact cause.
AP MAC Stats
The following MAC stats example is for an AP with perfect RF links to all SUs. (Note
- in this example ping traffic was being sent, so the number of cells transmitted and
received are equal).
192.168.100.200 hmm> mac stats
RXOK RXMISSED RXBAD TX
FDHDR: 0 0 0 134296
RGR: 4502 0 0 134296
ACK: 4887 0 0 4822
CELL: 13506 0 0 13506
tx 13506, inseq 13506, miss 0, dup 0
ticks (20mS) since last: utopia tx 0, utopia rx 0, FDHDR RXOK 237065
free list: head 141 tail 493 (delta 671)
Definition of terms
Acronym Interface Description
FDHDR Air interface Frame Description Headers (1 per frame at start of frame). Downlink only.
RGR Air interface Reservation Grant (downlink) or Reservation Request (uplink)
ACK Air interface Acknowledgements (downlink or uplink)
CELLS Air interface ATM traffic cells (downlink or uplink)
RXOK Air interface Correctly received, no errors
RXMISSED Air interface Expected, but not received (correlated, but sync word was wrong).
RXBAD Air interface Something was received with a CRC failure
TX Air interface ATM cells sent over RF link (includes re-tranmissions)
tx UTOPIA interface ATM cells entering MAC to be sent on air interface (excludes retransmissions)
inseq UTOPIA interface ATM cells received with expected sequence number
miss UTOPIA interface ATM cells received with sequence number wildly out
dup UTOPIA interface ATM cell received with sequence number too low (indicates a duplicated cell,
i.e. one that was retransmitted over the RF link, but was received both times).