Cisco Voice T1, E1, ISDN Configuration And Troubleshooting
Types of Signalling
1) Ground start signalling: 2) Supervisory signalling: off hook--connection between ring and tip wires-closed circuit on hook--open circuit Ringing 3) Information signalling: Dial tone , Busy, ringback, congestion, Re-order, receiver off hook 4) Address signalling: DTMF, Pluse
General Information
Tip ---->positive side of connection Ring---->negative side of connection Normally telephone is open circuit Loop start signalling--->when phone lifted, the phone connects two wires causing curre nt to flow from central office Glare occures in Loop start--Glare ----->when u pick the phone to dial number and simultaneously an incoming call comes and before before it has the chance to ring.
Digital Trunks:
CAS--Common associated signalling --signalling information is transmitted using same bandwidth as voice. CAS is sometimes called robbed-bit signaling because user bandwidth is robbed by the network for signaling. CCS--Common channel signalling --a separate channel is allocated for signalling part
T1 & E1
T1: Uses TDM to transmit digital data over 24 voice channels using CAS. There is no need for signalling channel since for CAS signalling is transferred with w ith data channel itself. CAS Provides receipt and capture of DNIS(dialed number identification service) and ANI(automatic number identification) The most common signalling used with T1 CAS is E&M signalling E1: Uses TDM to transmit digital data over 30 voice channels using either CAS or CCS. ISDN: Circuit switched telephone network system allowed to digital transmission of voice and data over ordinary copper wires. ISDN BRI :128 kb/s ;2 B channels; 1 D channel T1 PRI :1.5Mbps; 23 B channels ; 1 D channel PRI NFAS : Multiple ISDN PRI interfaces controlled by single D channel. QSIG: Interopeartion of PBX from different vendors.
Three types of digital voice circuits are available
1)T1 uses TDM to transmit 24 voice channels using CAS 2)E1 uses to transmit 30 voice channles using either CAS or CCS 3)ISDN: A circuited swicthed telephone network using CCS Ø BRI: 2 B (Bearer) channels and and 1 D (Delta) channel Ø T1 PRI: 23 B channels and 1 D channel Ø E1 PRI: 30 B channels and 1 D channel
Channels are known as DS0 channels, The ds0-group command creates a logical voice port (a DS0 D S0 group) from some or all of the t he DS0 channels
Two main types of CAS are
T1 CAS E1 R2 Trunk T1 CAS:
The type of signaling most commonly used with T1 CAS is E&M signaling The main disadvantage of CAS signaling is its use of user bandwidth to perform these signaling functions. The voice device running the T1 line uses the eighth bit on every ever y sixth FRAME in each T1 channel (DS0) for signalling. There are 24 Frames in a T1 Extendede super Frame, the t he process of signalling occurs for every sixth sixt h frame. 12 frames in super frame. Each DSO = 8 bits 24 DS0 = 8*24 +1 bit =193 bits ( 1 bit added was for framing bit) Digital T1 lines send 8000 of these 193-bit frames every second 8000*193 =1.5444Mbps
E1 R2
Ø A multiframe consists of 16 consecutive 256-bit frames. Ø Each frame carries 32 time time slots. Ø The first time slot is used exclusively for frame frame synchronization. Ø Time slots 2 to 16 and 18 to 32 carry the actual voice traffic, and time slot 17 is used for R2 signaling. Ø 16 Frames == Multi frame in E1 R2 Ø 1st frame--- time slot 17 is to declare the Frame as multiframe. Ø 2. Frame, Time slot 17: Signaling Signaling for time slots 2 and 18 Ø 3. Frame, Time slot 17: Signaling Signaling for time slots 3 and 19 Ø It goes on like tat
ISDN:
ISDN comprises digital telephony and data-transport services offered by regional te lephonecarriers. ISDN involves the digitization of the telephone network, which permits voice, data, text, graphics, music, video, and other source material to be transmitted overexisting telephone wires.
In contrast to the CAS and R2 signaling, which provide only DNIS, ISDN offers additional supplementary services such as Call Waiting and Do Not Disturb (DND). ISDN applications include high-speed image applications (such as Group IV facsimile), additional telephone lines in homes to serve the telecommuting industry, high-speed file transfer, and video conferencing. Voice service is also an application for ISDN. ISDN BRI: 2 bearer channel(64kbps) ( for voice traffic)+ tr affic)+ 1 D channel (16kbps)(D channel for signalling) ISDN PRI: 23 B + 1 D(64kbps) D (64kbps) in north america and 30 B +1 D in rest of the world T1 PRI: Use this interface to designate North American ISDN PRI with 23 B channels and one CCS channel E1 PRI: Use this interface to designate European ISDN PRI with 30 B channels, one CCS channel, and one framing channel. ISDN-PRI Nonfacility Associated Signaling (NFAS): Multiple ISDN PRI interfaces controlled by single D channel.
Benefits of ISDN:
ISDN has a built-in call control protocol known as ITU-T Q.931. ISDN supports call waiting, call forwarding,speed dialing T1 line encoding are B8ZS(binary 8-zero substitution), AMI and E1 line encoding are high-density bipolar 3(HDB3), AMI
CLOCKING:
free-running --not typical used(neither gets the clock nor it supplies) line --service provider is giving the clock internal ---u r providing the clock (in case u are connecting to pbx)
show network-clocks ----- command in order t o verify the clocking configuration
Single voice port receiving internal clocking. Line receives the clock from the PSTN Configuration : Router2(config)#controller Router2(config)#control ler T1 1/0 Router2(config-controller)#framing Router2(config-controlle r)#framing esf
Router2(config-controller)#linecoding Router2(config-controlle r)#linecoding am i Router2(config-controller)#clock Router2(config-controlle r)#clock source line Router2(config-controller)#ds0-group Router2(config-controlle r)#ds0-group timeslots 1-12 type e&m-wink-start
Internal clocking:
Internal clock supplies the clock to the t he PBX Router1(config)#controller Router1(config)#control ler T1 1/0 Router1(config-controller)#framing Router1(config-controlle r)#framing crc4 Router1(config-controller)#linecoding Router1(config-controlle r)#linecoding hdb3 Router1(config-controller)#clock Router1(config-controlle r)#clock source internal
Router1(config-controller)#ds0-group timeslots 1-15 type e&m-wink-start
Clock Prioritize when When two PSTN Lines are connected
network-clock-select 1 e1 0/0 network-clock-select 2 e1 0/1
By default WIC cards are disabled for receving the clock--so you have to configure w hich wic card will receive the clocking from PSTN. Go to the global configuration mode and type the command as below below network-clock-participate wic 1 (receving clock)
Note: When two or more controllers are configured for line, one should be designated as the primary clock source; it drives the other controllers.
Router(config-controlle)#clock Router(config-controlle )#clock source line primary Router(config-controlle)#clock Router(config-controlle )#clock source line secondary 1
Configuration of T1:
DSO groups:
Dso groups can be deactivated only when the voice port is deactivated. 1) Defines the T1/E1 channels for compressed voice calls 2) Automatically creates a logical voice port 3) Defines the emulated analog signaling method the router uses to connect to the PBX or PSTN
T1 CAS Controller Configuration Example
Enter controller configuration mode. Router(config)#controller Router(config)#control ler {t1 | e1} slot/port
Select frame type for T1 or E1 line. Note: The service provider determines the framing type that is required for your T1/E1 circuit
T1 Lines:
Router(config-controller)#framing Router(config-controlle r)#framing {sf | esf}
E1 Lines:
Router(config-controller)#framing Router(config-controlle r)#framing {crc4 | no-crc4} [Australia] Router(config-controller)#clock Router(config-controlle r)#clock source {line [primary | bits] |internal | free-running}
Define the T1 channels for use by compressed voice calls and the signalling method the router uses to connect to the PBX or CO.
Router(config-controller)#ds0-group Router(config-controlle r)#ds0-group ds0-group-number timeslots timeslot-list [service service-type] type {e&m-fgb | e&m-fgd | e&mimmediatestart | fgd-eana | fgd-os | fxs-ground-start | fxs-loop-start | none | r1-itu | r1-modified | r1-turkey}
The ds0-group command automatically creates a logical voice port. The resulting logical voice port will be 1/0:1, where 1/0 is the module and slot
number and :1 is the ds0-group-number argument you assign in this step.
5)Activate the controller. Router(config-controller)#no Router(config-controlle r)#no shutdown
Digital Voice Port Parameters
After setting up the controller, you can configure voice port parameters for that digital voice port. When you specified a ds0-group, the system automatically created a logical voice port
Enter voice-port configuration mode. Router(config)#voice-port Router(config)#voice-p ort slot/port:ds0-group-nu slot/port:ds0-group-number mber Router(config-voiceport)#cptone Router(config-voiceport)# cptone locale
Activate the voice port. Router(config-voiceport)#no Router(config-voiceport)# no shutdow
Configuring T1 CAS Trunks: Inbound E&M FGD and Outbound FGD EANA
Follow this procedure to configure a T1 CAS digital voice port with inbound and outbound ANI: Step 1. Enter controller configuration mode. Router(config)#controller Router(config)#control ler T1 0/0/0
Step 2. Specify the framing format. Router(config-controller)#framing Router(config-controlle r)#framing esf
Step 3. Specify line coding. Router(config-controller)#linecode Router(config-controlle r)#linecode b8zs
Step 4. Configure one DS0 group to use time slots 1 to 12 and E&M feature group-D. Router(config-controller)#ds0-group Router(config-controlle r)#ds0-group 0 timeslots 1-12 type e&m-fgd
Step 5. Configure another DS0 group to use time slots 13 through 24 2 4 and E&M feature group-D EANA. Router(config-controller)#ds0-group Router(config-controlle r)#ds0-group 1 timeslots 13-24 ty pe fgd-eana
Chapter 4: Performing Call Signaling over Digital Voice Ports 217 Note This creates two voice ports, 0/0/0:0 and 0/0/0:1. Step 6. An inbound dial peer is configured using the 0/0/0:0 trunk, which supports inbound ANI: Router(config)#dial-peerr voice 1 pots Router(config)#dial-pee Router(config-dialpeer)#incoming Router(config-dialpeer )#incoming called-number . Router(config-dialpeer)#port Router(config-dialpeer )#port 0/0/0:0
An outbound dial peer is configured using the 0/0/0:1 0/ 0/0:1 trunk, which supports outbound ANI: Router(config)#dial-peer voice 90 pots Router(config-dialpeer)#destination-pattern 9T Router(config-dialpeer)#port 0/0/0:1
Example T1 CAS Trunk Configuration Example
Router4(config)#controller Router4(config)#control ler T1 0/0/0 Router4(config-controller)#framing Router4(config-controlle r)#framing esf Router4(config-controller)#linecode Router4(config-controlle r)#linecode b8zs Router4(config-controller)#ds0-group Router4(config-controlle r)#ds0-group 0 timeslots 1-12 1 -12 type e&m-fgd Router4(config-controller)#ds0-group Router4(config-controlle r)#ds0-group 1 timeslots 13-24 13 -24 type fgd-eana Router4(config)#dial-peer Router4(config)#dial-p eer voice 1 pots Router4(config-dialpeer)#incoming Router4(config-dialpeer) #incoming called-number . Router4(config-dialpeer)#direct-inward-dial Router4(config)#dial-peer Router4(config)#dial-p eer voice 90 pots Router4(config-dialpeer)#destination-pattern Router4(config-dialpeer) #destination-pattern 9T Router4(config-dialpeer)#port Router4(config-dialpeer) #port 0/0/0:1
Example E1 R2 Trunk Configuration
Router5(config)#controller Router5(config)#control ler E1 0/0/0 Router5(config-controller)#ds0-group Router5(config-controlle r)#ds0-group 0 timeslots 1-31 type r2-digital r2-compelled ani Router5(config-controller)#cas-custom Router5(config-controlle r)#cas-custom 0 Router5(config-ctrl-cas)#country Router5(config-ctrl-cas)# country china use-defaults Router5(config)#dial-peer Router5(config)#dial-p eer voice 90 pots Router5(config-dialpeer)#destination-pattern Router5(config-dialpeer) #destination-pattern 9T Router5(config-dialpeer)#direct-inward-dial Router5(config-dialpeer)#port Router5(config-dialpeer) #port 0/0/0:0
Configuration of ISDN:
isdn incoming-voice: Configures the interface to send all incoming calls to the DSP card for processing proce ssing interface serial ---Enter voice port configuration mode for the D channel
Router(config)#isdn switch-type primary-qsig Router(config)#controller Router(config)#control ler t1 0/0 Router(config-controller)#pri-group Router(config-controlle r)#pri-group timeslots 1-24 Router(config-controller)#interface Router(config-controlle r)#interface serial 0/0:23 Router(config-if)#isdn Router(config-if)#isdn incoming-voice voice
Configuring a PRI Trunk Example
network-clock-participate wic 0 ----The DSP clocking will be synchronized with the WIC in slot 0. The line coding for the E1 controller contro ller will be linecoding ami-- default Router2(config)#interface Serial0/0/0:15---16 line will be the signalling channel
Performing Call Signaling over Digital Voice Ports 225 22 5 Router2(config)#network-clock-participate Router2(config)#network-cl ock-participate wic 0 Router2(config)#isdn switch-type primary-net5 Router2(config)#controller Router2(config)#controll er e1 0/0/0 Router2(config-controller)#pri-group Router2(config-controlle r)#pri-group timeslots 1-31 Router2(config)#interface Router2(config)#interfac e Serial0/0/0:15 Router2(config-if)#isdn switch-type primary-net5 Router(config-if)# isdn overlapreceiving
Router2(config-if)#isdn incoming-voice voice
Summary of voice ports:
Router#show controller T1 1/0/0 Router#show voice dsp Router#show voice call summary
show voice port summary -----command to identify the port numbers of voice interfaces installed in your router. show call active voice ---- command to display display the contents of the active call table, which shows all the calls currently connected through the router or concentrator. show call history voice ------command to display the contents of the call history history table.
QSIG:
Example Global QSIG Support Configuration for BRI Router(config)#isdn switch-type basic-qsig
Example Global QSIG Support Configuration for PRI Router(config)#isdn switch-type primary-qsig
Specify the card type (T1 or E1) at the specified slot so the router provides sufficient DSP resources. Router(config)#card type t1
Example QSIG over PRI PRI Interface Configuration
Router(config)#controller Router(config)#control ler t1 0/1 Router(config-controller)#pri-group Router(config-controlle r)#pri-group timeslots 1-24 Router(config)#interface serial 0/1:23 Router(config-if)#isdn Router(config-if)#isdn switch-type primary-qsig Router(config-if)#isdn Router(config-if)#isdn protocol-emulate user
Example QSIG over BRI Configuration Configuration
Router(config)#interface bri 1/1 Router(config-if)#isdn Router(config-if)#isdn layer1-emulate user Router(config)#interface bri 1/1 Router(config-if)#isdn Router(config-if)#isdn layer1-emulate network Router(config-if)#isdn Router(config-if)#isdn incoming-voice voice Router(config-if)#isdn Router(config-if)#isdn protocol-emulate user Router(config)#interface bri 1/1 Router(config-if)#isdn Router(config-if)#isdn protocol-emulate network
Example show isdn status Command
Router#show isdn status
The show isdn status command shows tat Layer 1 =active and layer 2="MULTIPLE_FRAME_ESTABLISHED" 2="MULTIPLE_FRAME_EST ABLISHED" indicates that there is no problem with layer 1 and 2
If a TEI_UNASSIGNED or AWAITING_ESTABLISHMENT state is reported, verify the configuration
Global ISDN Switchtype = primary-qsig ISDN Serial0/1/1:23 interface dsl 0, interface ISDN Switchtype = primary-qsig **** Slave side configuration **** Layer 1 Status: ACTIVE Layer 2 Status: TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED Layer 3 Status: 0 Active Layer 3 Call(s) Active dsl 0 CCBs = 0 The Free Channel Mask: 0x00000000 Number of L2 Discards = 0, L2 Session ID = 0 Total Allocated ISDN CCBs = 0
CONFIGURATION OF T1
You should get the following details from the service provider 1) Framing 2) Line coding 3) Clock source
Check using below commands
show controller t1 --->only shows the E1 or T1 and also the port/slot connected. show voice port summary show ip int brief
T1 configuration:
conf t controller t1 0/1/0 (slot/sub-unit/port) (slot/sub-unit/port) framing esf linecode b8zs clock source line no shutdown
CAS Digital Connections:
T1 ==24DS0 (Digital service level) 1 DSO =64Kbps
dso-group number is between 0 to 23 for T1 and 0 to 30 for E1. controller t1 0/1/0 ds0-group 0 timeslots 1-2 type e&m-immediate-start ds0-group 10 timeslots 1-4 type fxo-loop-start fxo-loop-start (fxo-loop start is mostly used in PSTN PSTN connection ) Note for troubleshooting: troubleshooting: Not enough DSP resources when getting configurating the t1-->limit the number of slots and try or else add dsp
CCS ISDN Configuration: Configuration:
After creating prigroup u will get the serial interfaces serial0/1/0:0 and will get voice port: voice-card 0/1/0:D port. conf t isdn swith-type primary-qsig controller t1 0/1/0 pri-group timeslots 1-4
When u configure then it u will be getting four serial ports serial0/1/0:0 serial0/1/0:1 serial 0/1/0:2 serial 0/1/0:3 There is additional port created for signalling and it is serial0/1/0:23
Configure the Interface(se I nterface(serial rial ports)
interface serial0/1/0:0
The following example for channelized T1 configures the D channel (hence, all B channels) to answer all incoming voice calls at 56 kbps:
interface serial 0:23 isdn incoming-voice data 56
NOTE: for full time slot assignment: assignment: pri-group timeslots 1-24 (T1) pri-group timeslots 1-31 (E1) another e.g pri-group timeslots 1-10,23 If the controller is of type T1, then the 24th timeslot is for the control information. information. ie., Serial x:23 functions as the D-channel. If the controller is of type E1, then the 16th timeslot is for the control information. information. ie., Serial x:15 functions as the D-channel.
Incoming call:
isdn incoming-voice voice -------->Configures incoming voice calls bypass the modems and be handled as a voice call.
isdn incoming-voice modem-->Incoming voice calls are passed over to the digital modems, wher e they negotiate the appropriate modem connection with the far-end modem. The incoming-voice modem command will allow the router (Gateway Example:AS5400) to process inbound calls (tones) for both voice and data. In other words, fax and modem tones as well as voice will w ill be handled accordingly
ISDN-QSIG:
isdn switch-type primary-qsig -----> PRI isdn switch-type basic-qsig
----> BRI
ISDN Status:
show isdn active----->Shows ISDN calls in progress show isdn history------>Shows ISDN call history show isdn status------->Shows ISDN line status show isdn timers-------->Shows ISDN timer values debug isdn events------->Displays ISDN events in real t ime debug isdn q921--------->Displays ISDN Q.921 packets in r eal time debug isdn q931 -------->Displays ISDN Q.931 packets in real time
Transparent CCS configuratio c onfiguration: n:
This is for Different signalling protocols(for e.g Nortel to communicate with nortel PBX over the WAN) For T1 its the 24 time slot slot used for signalling signalling and E1 16 time slot conf t controller t1 0/1/0 ds0-group 23 timeslot 24 type ext-sig
T1 & E1
T1: Uses TDM to transmit digital data over 24 voice channels using CAS. There is no need for signalling channel since for CAS signalling is transferred with w ith data channel itself. CAS Provides receipt and capture of DNIS(dialed number identification service) and ANI(automatic number identification) The most common signalling used with T1 CAS is E&M signalling E1: Uses TDM to transmit digital data over 30 voice channels using either CAS or CCS. ISDN: Circuit switched telephone network system allowed to digital transmission of voice and data over ordinary copper wires. ISDN BRI :128 kb/s ;2 B channels; 1 D channel T1 PRI :1.5Mbps; 23 B channels ; 1 D channel PRI NFAS : Multiple ISDN PRI interfaces controlled by single D channel.
QSIG: Interopeartion of PBX from different vendors.
Configuration Configuration Examples:
The following example shows how to configure a basic channelized E1 PRI PR I ISDN port adapter. In this example, the controller is enabled, timeslots are assigned to the PRI group, and the ISDN switch type used on all ISDN interfaces on the router r outer is a switch for the European community (primary-net5). The PRI group timeslots of 1, 3, 4, 5, and 7 (the B channels) are selected to map to timeslot 16 (the D channel), which is recognized by the system as timeslot 15.
Router# configure terminal Router (config)# isdn switch-type primary-net5 Router (config)# controller e1 3/1/1 Router (config-controller)# framing crc4 Router (config-controller)# linecode hdb3 Router (config-controller)# pri-group timeslots 1,3-5,7 Router (config-controller)# exit
Router (config)# interface serial 3/1/1:30 Router (config-if)# ip address 1.1.15.1 255.255.255.0 Router (config-if)# end
The following example shows how to configure a basic channelized T1 PRI PR I ISDN port adapter. In this example, the controller is enabled, timeslots are assigned to the PRI group, and the ISDN switch type used on all ISDN interfaces on the router r outer is for the United States S tates switch (primary-5ess). The PRI group timeslots of 1, 3, 4, 5, and 7 (the B channels) are selected to map to timeslot t imeslot 24 (the D channel), which is recognized by the system as timeslot 23.
Router# configure terminal Router (config)# isdn switch-type- primary-5ess Router (config)# controller t1 3/1/1
Router (config-controller)# framing esf Router (config-controller)# linecode b8zs Router (config-controller)# pri-group timeslots 1,3-5,7 Router (config-controller)# exit Router (config)# interface serial 3/1/1:23 Router (config-if)# ip address 1.1.15.1 255.255.255.0 Router (config-if)# end Router#
The following example shows channel group 0 and timeslots 1, 3 through 5, and 7 selected for mapping. The example shows how to configure a basic channelized E1 port adapter on a Cisco 7200 series router:
Router# configure terminal Router (config)# controller e1 1/1 Router (config-controller)# clock source line Router (config-controller)# framing crc4 Router (config-controller)# linecode hdb3 Router (config-controller)# (config-controller)# channel-group 0 timeslots 1,3-5,7 ( channel group groups groups the time slot and convert to single channel) Router (config)# interface serial 1/1:0 Router (config-if)# ip address 1.1.15.1 255.255.255.0 Router (config-if)# end Router #
T1 or E1 Interface Troubleshooting Troubleshooting
To troubleshoot the T1 or E1 interface, inter face, perform the following steps:
SUMMARY STEPS ·
show controller {t1 | e1}
·
Check if the line is down.
·
Check for reported alarms.
·
Check for error events.
·
Check if the interface is T1 or E1 CAS, E1 R2, or PRI.
Controller Has Loss of Frame:
Put command show controller {t1 | e1}. If there is any loss of frame try changing the frame type. If the first framing format does not work, try the other framing format to see if the alarm clears.
Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# controller t1 0 Router(config-controlle)# framing esf
For T1 lines, change the line build-out using the cablelength long or cablelength short command. Contact your service provider for framing and line coding settings. Common settings are as follows: For T1 lines, it is common c ommon to use binary 8-zero substitution (B8ZS) line coding with ext ended superframe (ESF), and alternate mark inversion (AMI) line coding with superframe (SF). For E1 lines, both HDB3 and AMI line coding co ding are available, but CRC4 framing is most widely used.
E.G OF SHOW CONTROLLER COMMAND:
show controllers t1 0
T1 0 is up. Applique type is Channelized T1 Cablelength is long gain36 0db
No alarms detected. Version info of slot 0: HW: 4, Firmware: 16, PLD Rev: 0 Manufacture Cookie Info: EEPROM Type 0x0001, EEPROM Version 0x01, Board ID 0x42, Board Hardware Version 1.32, Item Number 73-2217-5, 73 -2217-5, Board Revision B16, Serial Number 09356930, PLD/ISP Version 0.0, Manufacture Date 18-Jun-1998. 18 -Jun-1998. Framing is ESF, Line Code is B8ZS, Clock Source is Line Primary. Data in current interval (8 seconds seco nds elapsed): 0 Line Code Violations, 0 Path Code Violations 0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins 0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs
The main items to look at in the above output is
1)The status of the line 2)Alarms Linecode and Pathcode violations 3) Slip Secs: If timing differs then voice quality,noice problems in in the call arises In most cases, you can check for clock slips on the E1 or T1 interface in order to confirm the problem. Issue the show controller {e1 | t1} command for confirmation:
Router# show controller e1 0/0
E1 0/0 is up. Applique type is Channelized E1 - balanced No alarms detected. alarm-trigger is not set Version info Firmware: 20020812, FPGA: 11
Framing is CRC4, Line Code is HDB3, Clock Source is Line. Data in current interval (97 seconds elapsed): e lapsed): 0 Line Code Violations, 0 Path Code Violations 4 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins 4 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs A common message you will see in the alarm field is "receiver has loss of frame." ---->check framing is correct Another message you might receive is "receiver is getting AIS." ----->This means the receiver re ceiver is getting an alarm indication signal (blue alarm) This is typically seen when the far-end CSU C SU has lost its terminal side equipment. The "receiver has remote alarm" indicates the presence of a yellow alarm. This means the downstream CSU is in a loss-offrame or loss-of-signal state. Therefore, the remote CSU has a red alarm. The "transmitter is sending remote alarm" indicates that the local CSU has detected either a loss-offrame or loss-of-signal condition Always verify framing and T1 signal when troubleshooting this problem. Whenever you are troubleshooting a T1, always verify that both-sides of the circuit are running clean. It is possible that only one side of the T1 is seeing errors. Remember, that the T1 is going only between you and the provider. Always contact the provider t o make sure they aren't seeing se eing errors on their side of the circuit.
Troubleshooting the ISDN connection: show isdn status
E.g output of the command:
ISDN BRI3/0 interface dsl 16, interface ISDN Switchtype = basic-ni Layer 1 Status: ACTIVE Layer 2 Status: TEI = 64, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED MULTIPLE_FRAME_ESTABLISHED TEI = 73, Ces = 2, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED MULTIPLE_FRAME_ESTABLISHED TEI 64, ces = 1, state = 5(init)
spid1 configured, spid1 sent, spid1 valid Endpoint ID Info: epsf = 0, usid = 0, tid = 1 TEI 73, ces = 2, state = 5(init) spid2 configured, spid2 sent, spid2 valid Endpoint ID Info: epsf = 0, usid = 1, tid = 1 Layer 3 Status: 0 Active Layer 3 Call(s) Active dsl 16 CCBs = 0 The Free Channel Mask: Mask: 0x80000003 Total Allocated ISDN CCBs = 0
To determine whether everything is copacetic, you should l ook for three main things in this output: Layer 1 Status should say Active. Layer 2 Status should say MULTIPLE_FRAME_ESTABLISHED. Under Layer 2, spid1 and spid2 should both say configured and valid.
If Layer 1 is down Calling the carrier and opening a ticket for a Layer1 Down status, let's keep ke ep investigating. On the interface, try using the clear isdn interface bri0/0 command and the no shutdown command.
REFERENCE WEBPAGES: http://ccie-security.blogspot.com/2008/10/t1-wierdness.html
http://docwiki.cisco.com/wiki/Cisco_IOS_Voice_Troubleshooting_and_Monitoring_- _T1_or_E1_Interface_Troubleshooting#Troubleshooting_T1_an _T1_or_E1_Interface_Troubl eshooting#Troubleshooting_T1_and_E1_Layer_1_Problems d_E1_Layer_1_Problems
