GSM BTS Over IP Deployment Troubleshooting Guide

HUAWEI TECHNOLOGIES CO., LTD.

www.huawei.com

Huawei Confidential

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2011-9-27

GSM BTS over IP Deployment Troubleshooting Guide

GSM Network I&V and Maintenance Dept.WN

Internal use

HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential

SNVersion Number

Date Change Description Author

1 V1.0 2011-7-31Technical guide to GSM BTS over IP deployment

Huang Gang

2 V2.0 2011-8-31GSM BTS over IP deployment troubleshooting guide

Liu Ping

3 V2.1 2011-9-23 Revised based on the comments Liu Ping

Change History


Contents

Prerequisites for GBSS over IP Deployment

GSM BTS over IP Deployment Procedure

GSM BTS over IP Deployment Methods

GSM BTS over IP Deployment

Troubleshooting

Cases


Prerequisite for GBSS over IP Deployment (on the BSC)

Start

Check whether a built-in PCU exists

Add an IP interface board

Check whether the license of the IP feature is

obtained

End

Use a built-in PCU

Add a DPUc

Apply for and activate a new license

N

N

N

Y

Y

Y

Check whether a DPUc is installed in

the BM subrack


Prerequisite for GBSS over IP Deployment (on the BTS)

3900 series BTS 3012 series BTS

Start

End

Upgrade the BTS3900

software versionN

Y

Check whether the BTS3900 software

supports IP transmission

Start

End

Upgrade the BTS3900

software versionN

Y

Add a PTU board

Check whether the BTS3900 software supports

IP transmission


Contents




GSM BTS over IP Deployment Troubleshooting

Cases



Preliminary requirements on BTS deployment

1. On the site, perform hardware installation, connection, and power-

on.

2. On the OMC, perform GBTS data configuration and software

upload.

3. Purpose: The BSC assigns a service IP address to the GBTS

through message interaction. The GBTS establishes a maintenance

channel to the BSC/M2000 by using this IP address and downloads

software and configuration from the BSC/M2000 on this channel. In

this way, the GBTS establishes communication with the

BSC/M2000.


General BTS Deployment Procedure

Network

GBTS BSC M2000

Ma

nu

al

op

era

tion

Te

chn

ica

l im

ple

me

nta

tion

Au

tom

atic

im

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GBTS hardware installation, transmission connection, power-on, and GBTS data configuration

Establishment of maintenance channels between the BSC and GBTS

Downloading of GBTS configuration and software, establishment of maintenance channels, and normal provisioning of services

End


BTS Deployment Procedure Decomposition

Phase 1Perform detection by checking the records in the

flash memory

IP over FE

Phase 3

Perform detection in IPoE1/IPoT1 typical timeslot mode

TDM/HDLC

Phase 2

Tim

e ax

is

阶段4

Phase 5

Perform detection in IPoE1/IPoT1 non-typical timeslot mode

Send a message to the OM after the detection

IP over FE TDM/HDLC

Six minutes

Six minutes

Six minutes

Five minutes

Phase 4

Three minutes

Network

Report ESNs to the OMC.

Install and power on the hardware.

Allocate ESNs.

Enable VLAN detection (optional).

Synchronize the GBTS.

Upload the software.

GBTS BSC M2000

Ma

nua

l op

era

tion

DH

CP

tec

hnic

al

imp

lem

en

tatio

n

Au

tom

atic

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tion

Configure GBTS through MML commands.

Phase 2: This phase lasts six minutes. Perform DHCP polling in IPoFE mode. At the same time, send a link establishment request in a specific timeslot in TDM/HDLC mode. If both procedures fail, go to phase 3. Otherwise, download configuration.

Phase 1: This phase lasts three minutes. Read the link information of the previous successful DHCP procedure saved in the flash memory and originate a new DHCP procedure on the link. The flash memory is empty during GBTS deployment. Therefore, the new DHCP procedure must fail. Go to phase 2.

Phase 3: This phase lasts six minutes. In IPoE1/IPoT1 typical timeslot mode, perform DHCP polling. If the procedure fails, go to phase 4. Otherwise, download configuration (currently, DHCP polling cannot be performed in IPoFE mode in this phase).

Phase 4: This phase lasts six minutes. Perform DHCP polling in IPoFE mode. At the same time, send a link establishment request in a specific timeslot in TDM/HDLC mode. If both procedures fail, go to phase 5. Otherwise, download configuration.

Phase 5: This phase lasts five minutes. In IPoE1/IPoT1 non-typical timeslot mode, perform DHCP polling. If the procedure fails, reset the GBTS. Otherwise, download configuration.

Reset the GBTS and return to phase 1.

Download configuration or software.

Configuration or software takes effect.

The GBTS is normal.

GBTS deployment ends.


GSM BTS over IP Link Establishment Procedure

1. The detection procedure is normal.

2. The DHCP procedure is normal.

3. The L2ML link is established.

4. The ESL link is established.

5. The OML link is established.


Contents





Cases


Router L2

BSC（DHCP Server）GBTS（DHCP Client） Router（DHCP Relay）

L2

VLAN Detect (UDP broadcast packet; optional) VLAN Detect (unicast packet; optional)

DHCP Discover (unicast packet, including the ESN)

DHCP Offer (broadcast packet) DHCP Offer (unicast packet; verifying the ESN before sending an IP address)

DHCP Request (broadcast packet; similar to DHCP Discover) DHCP Request (unicast packet; similar to

DHCP Discover)

DHCP ACK (broadcast packet; similar to DHCP Offer)

DHCP ACK (unicast packet; similar to DHCP Offer)

The DHCP client obtains a temporary IP address and therefore establishes a connection with the DHCP server.

DHCP Discover (UDP broadcast packet, including the ESN)

BTS Remote Deployment in Layer 3 Networking

In layer 3 networking, the BTS obtains an IP address through the DHCP client. Therefore, the router nearest to the BTS must support the DHCP relay function. If the router does not support this function, the BTS is deployed by using the local static IP address.


GBTS（DHCP Client）

L2

VLAN Detect (UDP broadcast packet that is learnt by the GBTS after received; optional)

DHCP Offer (UDP broadcast packet; verifying the ESN before sending an IP address)

DHCP Request (similar to DHCP Discover)

DHCP ACK (similar to DHCP Offer)

The DHCP client obtains a temporary IP address and therefore establishes a connection with the DHCP server.

DHCP Discover (UDP broadcast packet, including the ESN; transmitted on port 67/6)

BSC（DHCP Server）

BTS Remote Deployment in Layer 2 Networking

In layer 2

networking, the

DHCP relay function

does not need to be

enabled on

transmission

network devices.

The BTS sends a

DHCP DISCOVER

message which can

be broadcast to the

BSC.


Parameter configuration

Parameter configuration

CSP file

BTS Local Deployment by Using the USB Disk

1. Prepare site data and software.

2. Implement USB commissioning.• If the BTS version is inconsistent with the software version in the USB

disk, the BTS loads the software version from the USB disk.• If the configuration in the flash memory of the BTS control board is

inconsistent with the transmission configuration file in the USB disk, the

BTS automatically upgrades the data configuration file.


BTS Local Deployment by Using the USB Disk

3. Precautions USB commissioning applies to the scenario where intermediate devices

do not support the DHCP relay function or operators do not accept the DHCP procedure.

USB commissioning applies to only IPoFE or IPoE1 BTSs. Within three minutes after startup, the BTS cannot be upgraded or

configured by using the USB disk. The USB disk does not support upgrade of hot patches, BootROM, or the

software of other boards. Currently, the USB disk can contain only one GBTS configuration file. GBTS data is saved in the configuration file after the parameters

required for GBTS startup are modified by using MML commands through the CME. The configuration file saved in the USB disk is copied to the GBTS for link establishment.

The USB indicator and control board indicator are in different states while data or software becomes effective. For more information, see the FAQ.


Contents




GSM BTS over IP Deployment

Troubleshooting

Cases



The following troubleshooting methods can be used for locating not

only BTS deployment problems but also common transmission

problems. See the IP troubleshooting guide.

1. Check the E1/T1 physical layer.

2. Check the FE/GE physical layer.

3. Check the ARP/IP layer.

4. Solve PPP/MP abnormalities.

5. Solve LAPD signaling link abnormalities.



1. Determine the BTS and BSC versions and check whether BTS deployment problems are known.

2. Check whether the BTS is deployed locally or remotely.

3. Check the USB disk used for BTS deployment.

(1) Check whether the BTS reads the USB configuration.

Connect the USB disk to the BTS through a serial port or Telnet, and run dir, cd config, and dir in

sequence to check whether the TranCfg.ini file exists. If this file exists, the BTS has read the USB

configuration.

(2) Check whether the USB data is correct.

1. The ESN is correct.

2. The BTS transmission type, IP address, and VLAN are correct.

3. Routes exist. A common problem is that no route exists. The configuration file is exported by using the CME. Generally, if the BTS is

deployed using a dynamic IP address, no BTS uplink route needs to be configured on the BSC/CME (the BTS generates a default

route). Therefore, the exported script does not contain the route information. In a BTS deployment scenario by using the USB disk, the

route is necessary. The BTS first checks whether a route exists when reading the configuration file in the USB disk. If no route exists,

the BTS does not use the parameters in the configuration file. In this case, you can manually enter the route information and run the

ADD BTSIPRT command to configure the BTS uplink route on the BSC/CME. Alternatively, you can configure the BTS uplink route on

the BSC/CME and then export the script to the USB disk for BTS deployment. A script is attached for reference. Engineers can modify

or supplement the script as required.

Note: In layer 2 networking, the route must also be configured if the BTS is deployed by using the USB disk. Otherwise, BTS deployment fails.


4. Ping the BTS on the BSC.The MML command used for pinging an IP address is as follows:

PING IP: SRN=0, SN=24, SIPADDR="10.0.0.1", DESTIP="10.0.0.2", CONTPING=YES, PKTSIZE=1430, DSCP=48;

Parameter description SRN and SN are set to the number of the interface board of the BTS. SIPADDR is set to the IP address of the BSC configured in the SET BTSIP command. It is a service IP address

on the BSC. DESTIP is set to the IP address of the BTS. PKTSIZE is set to 64, 200, and 1430 respectively. DSCP is set to the signaling DSCP value. By default, it is set to 48. The value is set as required.

If the BTS is deployed locally, ping the BTS for more than 15 minutes. If the ping succeeds,

the DHCP procedure is successful, and the procedure after L2ML establishment may fail. If

the BTS can be pinged for only six minutes, the DHCP unicast procedure fails.

If the BTS is deployed remotely, ping the BTS for more than 15 minutes. If the ping

succeeds, the DHCP procedure is successful, and the procedure after L2ML establishment

may fail. If the BTS cannot be pinged, the DHCP broadcast procedure fails.


HUAWEI TECHNOLOGIES CO., LTD. Huawei Confidential Page 20


5. Analyze DHCP abnormalities.Common DHCP abnormalities are DHCP procedure failure and site loading

failure for a long time.(1) Check whether transmission abnormalities exist according to the IP troubleshooting guide.

(2) Check the basic BSC configuration.

On the BSC, run the LST BTSESN command to check whether BTSESN is set.

On the BSC LMT, run the LST IPRT command to check whether the route configuration is correct and

complete. In layer 3 networking, in addition to the route to the BTS, the route to the BTS gateway (the

DHCP relay function is enabled) must be configured.

Check the BTS VLAN configuration and make sure that all types of data are tagged with VLAN IDs.

If the BTS is configured with VLANs, enable the VLAN detection function on the BSC to remotely

commission the BTS. Run the SET BTSOTHPARA command to set BTSDETECTSWITCH to OPEN. This

parameter is the BTS detection switch. When it is set to CLOSE, the BTS detection function is disabled;

when it is set to OPEN, the BTS detection function is enabled. After the detection function is enabled, the

BSC addresses the BTS based on the BTS IP address and sends a UDP packet carrying the VLAN ID to

the BTS. Disable the detection function after the BTS is commissioned remotely.



Page 21

(3) Check intermediate router configuration. If the Abis interface uses layer 3 networking, make sure that the DHCP relay is configured on the gateway

router near to the BTS. DHCP configuration faults are likely to occur after transmission is commissioned.

If layer 2 switch devices such as PTN devices or switches are involved in the transmission over the Abis

interface, locate the problem as follows:

For the PTN devices, check the port attribute (Access, Tag Aware, or Hybrid). In Tag Aware mode, the port

rejects packets that are not tagged with VLAN IDs.

For the layer 2 switches, check whether the VLAN configured is consistent with that configured on the BTS.

(4) Check whether the BSC receives DHCP packets carrying ESNs that are not configured.

On the BSC LMT, run the CLR BTSESN command and then run the DSP BTSESN command after five minutes. If

the ESNs in the received packets are not configured on the BSC, the ESNs may be incorrectly configured.

Modify the ESNs.



(5) Check whether packet reception and transmission are normal.

The procedure is as follows: By performing packet capture on the local port mirrored or performing packet capture on the interface

board, check whether the BSC receives DHCP packets.

If the BTS reports a DHCP Discovery packet but the BSC does not send a response, check whether

the BSC configuration (route configuration) is complete and whether the ESNs are correct.

If the BSC does not receive the DHCP Discovery packet and the BTS powered on is a BTS restarted

due to upgrade, you can determine that the problem occurs on the intermediate network. If the BTS

powered on is a new BTS, you can also determine that the problem occurs on the intermediate

network after checking that the BTS hardware is normal.

If no problem is found and the BTS still cannot be started, query BTS logs or capture packets on the

local port mirrored to check whether the BTS sends a DHCP Discover or DHCP Request packet and

whether layer 2 links are normally established.

See the following attachments for BTS log analysis and BSC packet capture.

BTS3900 GSM Transmission Log Analysis Gu

Guide to MBSC Packet Capture Function ¡ª


(6) Check whether abnormalities exist after the DHCP procedure.

Check whether the subsequent procedure is normal after the DHCP procedure. If

the gateway of the BTS configured with the DHCP relay sends an incorrect IP

address of the next hop (the DHCP relay interface of the gateway is configured

with multiple IP addresses), the BTS sends a DHCP RELEASE message after the

DHCP procedure. In this case, check the gateway configuration.



Contents





Cases


In an office, after BSC upgrade, a great number of BTS OML link

break alarms are generated and exist for a long time.

Handling procedure 1. By performing packet capture on the BSC interface board. The

BSC does not receive the DHCP packets sent by the BTS.

2. Analyze scripts. No abnormality is found.

3. Switch over the boards. The fault persists.

4. Ask the customer to check transmission devices. The customer

finds that DHCP configuration is incorrect.

Case 1


Problem description On the network of N4W Sweden, the BTS over IP is powered off. When a

dynamic IP address is used, the BTS cannot be started. When a static IP

address is used, the BTS can be started. Analyze why the BTS using a dynamic

IP address cannot be started.

Onsite version V900R012ENGC01SPC500

Onsite networking feature

A BTS interface on which the DHCP relay is enabled is configured with multiple IP

addresses.

Question

What information needs to be collected?

Case 2

Failing to Load the BTS by Using a Dynam

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