ISDN BRI Terminal Endpoint Identifier Negotiation

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Updated:September 9, 2005
Document ID:12073

Bias-Free Language

The documentation set for this product strives to use bias-free language. For the purposes of this documentation set, bias-free is defined as language that does not imply discrimination based on age, disability, gender, racial identity, ethnic identity, sexual orientation, socioeconomic status, and intersectionality. Exceptions may be present in the documentation due to language that is hardcoded in the user interfaces of the product software, language used based on RFP documentation, or language that is used by a referenced third-party product. Learn more about how Cisco is using Inclusive Language.

Introduction

This document provides a sample configuration for ISDN Basic Rate Interface (BRI), and illustrates Cisco router behaviour with regard to the terminal endpoint identifier (TEI) negotiation process.

Prerequisites

Requirements

There are no specific requirements for this document.

Components Used

The information in this document is based on these software and hardware versions:

  • Cisco IOS?? Software Release 12.2(6).

  • All hardware platforms.

Note: The isdn tei-negotiation preserve command was introduced in Cisco IOS Software Releases 12.2(6) and 12.2(6)T.

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

For more information on document conventions, refer to Cisco Technical Tips Conventions.

Background Information

In some European countries (such as, Belgium and Holland), the usual practice is that the Telephone Company (Telco) disconnects ISDN Layer1 when the BRI line has not been active for a certain period, due to power save reasons. These alternatives are possible:

  • TEIs that have already been assigned can be preserved after Layer 1 stops flapping.

  • The Cisco IOS Software can be configured to re-negotiate the TEI every time Layer 1 flaps.

Configure

In this section, you are presented with the information to configure the features described in this document.

Note: To find additional information on the commands used in this document, use the Command Lookup Tool (registered customers only) .

Network Diagram

This document uses this network setup:

bri_isdn_callback.gif

In this example, we are using two Cisco 2500 routers with BRI lines.

Configurations

This document uses these configurations:

  • kevin

  • krimson

kevin 
kevin#show running-config
!
version 12.2                                                
service timestamps debug datetime msec
service timestamps log datetime msec
hostname kevin
!
username krimson password 
!
isdn switch-type basic-net3
!
interface BRI0
no ip address
encapsulation ppp
dialer rotary-group 1
dialer-group 1
isdn switch-type basic-net3
isdn tei-negotiation preserve
no cdp enable
ppp authentication chap
!
interface Dialer1
ip address 10.9.8.2 255.255.255.0
encapsulation ppp
dialer in-band
dialer map ip 10.9.8.1 name krimson 027208196
dialer-group 1
no cdp enable
ppp authentication chap
!
dialer-list 1 protocol ip permit
!
line con 0
 exec-timeout 0 0
line aux 0
line vty 0 4
 exec-timeout 0 0
 password 
 login
!
end

krimson 
krimson#show running-config
!
version 12.2                                                
!
service timestamps debug datetime msec
service timestamps log datetime msec
!
hostname krimson
!
username kevin password 
!
isdn switch-type basic-net3
!
interface BRI0
no ip address
encapsulation ppp
no ip route-cache
no ip mroute-cache
no keepalive
dialer rotary-group 1
isdn switch-type basic-net3
no fair-queue
no cdp enable
ppp authentication chap
!
interface Dialer1
ip address 10.9.8.1 255.255.255.0
encapsulation ppp
no ip route-cache
no ip mroute-cache
load-interval 30
no keepalive
dialer in-band
dialer map ip 10.9.8.2 name kevin 027202094
dialer-group 1
no fair-queue
no cdp enable
ppp authentication chap
!
dialer-list 1 protocol ip permit
!
line con 0
 exec-timeout 0 0
line aux 0
line vty 0 4
 exec-timeout 0 0
 password 
 login
!
end

Verify

This section provides information you can use to confirm your configuration is working properly.

Certain show commands are supported by the Output Interpreter Tool (registered customers only) , which allows you to view an analysis of show command output.

  • show isdn status???displays the status of all ISDN interfaces.

kevin#show isdn status
Global ISDN Switchtype = basic-net3
ISDN BRI0 interface
dsl 0, interface ISDN Switchtype = basic-net3
Layer 1 Status:
DEACTIVATED
Layer 2 Status:
Layer 2 NOT Activated  

!--- TEI is removed

Layer 3 Status:
0 Active Layer 3 Call(s)
Active dsl 0 CCBs = 0
The Free Channel Mask:  0x3
Number of L2 Discards = 0, L2 Session ID = 10
Total Allocated ISDN CCBs = 0

Troubleshoot

This section provides information you can use to troubleshoot your configuration.

Troubleshooting Commands

Note: Before issuing debug commands, refer to Important Information on Debug Commands.

  • debug isdn q921???displays data link layer (layer 2) access procedures that are taking place at the router on the D channel (LAPD) of its ISDN interface.

  • debug isdn q931???displays information about call setup and teardown of ISDN network connections (layer 3), between the local router (user side) and the network.

  • debug isdn events???displays ISDN events occurring on the user side (on the router) of the ISDN interface.

  • debug bri???displays debugging information on ISDN BRI routing activity.

Here is the debug output on kevin:

kevin#
*Mar  1 03:04:14.235: BRI: write_sid: scp = 0, wrote = 92
*Mar  1 03:04:14.235: BRI: write_sid: scp = 80, wrote = 93
*Mar  1 03:04:14.239: BRI0: DEACTIVATED, state F1, event LSD
*Mar  1 03:04:14.243: BRI: write_sid: scp = 0, wrote = 1B
*Mar  1 03:04:14.243: BRI: write_sid: scp = 0, wrote = 20
*Mar  1 03:04:14.243: BRI: write_sid: scp = 0, wrote = 92
*Mar  1 03:04:14.247: BRI: write_sid: scp = A0, wrote = 93
*Mar  1 03:04:14.247: BRI0: DEACTIVATED, state F3, event AP
*Mar  1 03:04:14.251: BRI: write_sid: scp = 0, wrote = 3
*Mar  1 03:04:14.255: ISDN BR0: Recvd MPH_IIC_IND from L1
*Mar  1 03:04:14.263: BRI: write_sid: scp = 0, wrote = 92
*Mar  1 03:04:14.263: BRI: write_sid: scp = E0, wrote = 93
*Mar  1 03:04:14.267: BRI0: PENDING, state F7, event AI
*Mar  1 03:04:14.267: BRI: Received activation indication.
*Mar  1 03:04:14.271: Flush all frames in the queue if any
*Mar  1 03:04:14.275: ISDN BR0: L1 is IF_ACTIVE
*Mar  1 03:04:14.275: ISDN BR0 EVENT: isdn_sw_cstate: State = 4, Old State = 4
*Mar  1 03:04:14.279: ISDN BR0: Incoming call id = 0x0030, dsl 0
*Mar  1 03:04:14.319: ISDN BR0: TX -> IDREQ ri=65279 ai=127
*Mar  1 03:04:14.323: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:04:14.355: ISDN BR0: RX <- IDASSN ri=65279 ai=66
*Mar  1 03:04:14.375: ISDN BR0: TX -> SABMEp c/r=0 sapi=0 tei=66
*Mar  1 03:04:14.379: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:04:14.399: ISDN BR0: RX <- UI c/r=1 sapi=0 tei=127
i=0x08011C05A1040288901801896C0A218332373230383139367009A13237323032303934
*Mar  1 03:04:14.435: SETUP pd = 8  callref = 0x1C
*Mar  1 03:04:14.443:   Sending Complete
*Mar  1 03:04:14.443:   Bearer Capability i = 0x8890
*Mar  1 03:04:14.451:   Channel ID i = 0x89
*Mar  1 03:04:14.455:   Calling Party Number i = 0x21, 0x83,
'27208196', Plan:ISDN, Type:National
*Mar  1 03:04:14.475:   Called Party Number i = 0xA1, '27202094',
Plan:ISDN, Type:National
*Mar  1 03:04:14.495: ISDN BR0: RX <- UAf c/r=0 sapi=0 tei=66
*Mar  1 03:04:14.503: %ISDN-6-LAYER2UP: Layer 2 for Interface BR0, TEI 66
changed to up
*Mar  1 03:04:14.515: CCBRI_Go Fr L3 pkt (Len=35) :
*Mar  1 03:04:14.515: 5 1 9C 90 A1 4 2 88 90 18 1 89 6C A 21 83 32 37 32 30
38 31 39 36 70 9 A1 32 37 32 30 32 30 39 34
*Mar  1 03:04:14.527:
*Mar  1 03:04:14.531: ISDN BR0: Incoming call id = 0x0031, dsl 0
*Mar  1 03:04:14.535: ISDN BR0: LIF_EVENT: ces/callid 1/0x31
HOST_INCOMING_CALL
*Mar  1 03:04:14.543: ISDN BR0: HOST_INCOMING_CALL: (non-POTS) DATA
*Mar  1 03:04:14.543: ISDN BR0: HOST_INCOMING_CALL: (1) call_type = DATA
*Mar  1 03:04:14.547: ISDN BR0: HOST_INCOMING_CALL: voice_answer_data =
FALSE call type is DATA
*Mar  1 03:04:14.551: ISDN BR0: Event: Received a DATA call from 27208196
on B1 at 64 Kb/s
*Mar  1 03:04:14.551: ISDN BR0: Event: Accepting the call id 0x31
*Mar  1 03:04:14.555: ISDN BR0: RM returned call_type 0 resource type 0
response 1
*Mar  1 03:04:14.559: CCBRI_Go Fr Host InPkgInfo (Len=9) :
*Mar  1 03:04:14.563: 7 0 1 0 31 3 18 1 89
*Mar  1 03:04:14.567:
*Mar  1 03:04:14.575: ISDN BR0: isdn_send_connect(): msg 4, call id 0x31,
ces 1 bchan 0, call type DATA
*Mar  1 03:04:14.579: BRI: enable channel B1
*Mar  1 03:04:14.579: %LINK-3-UPDOWN: Interface BRI0:1, changed state to up
*Mar  1 03:04:14.591: ISDN: get_isdn_service_state(): idb 0x230B74 bchan 2
is_isdn 1 Not a Pri
*Mar  1 03:04:14.595: CCBRI_Go Fr Host InPkgInfo (Len=6) :
*Mar  1 03:04:14.599: 4 0 1 0 31 0
*Mar  1 03:04:14.603:
*Mar  1 03:04:14.615: ISDN BR0: TX -> INFOc sapi=0 tei=66 ns=0 nr=0
i=0x08019C02180189
*Mar  1 03:04:14.627: CALL_PROC pd = 8  callref = 0x9C
*Mar  1 03:04:14.631: Channel ID i = 0x89
*Mar  1 03:04:14.639: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:04:14.663: ISDN BR0: RX <- RRr sapi=0 tei=66 nr=1
*Mar  1 03:04:14.675: ISDN BR0: TX -> INFOc sapi=0 tei=66 ns=1 nr=0
i=0x08019C07
*Mar  1 03:04:14.679: CONNECT pd = 8  callref = 0x9C
*Mar  1 03:04:14.687: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:04:14.711: ISDN BR0: RX <- RRr sapi=0 tei=66 nr=2
*Mar  1 03:04:15.567: ISDN BR0: RX <- INFOc sapi=0 tei=66 ns=0 nr=2
i=0x08011C0F
*Mar  1 03:04:15.575: CONNECT_ACK pd = 8  callref = 0x1C
*Mar  1 03:04:15.595: ISDN BR0: TX -> RRr sapi=0 tei=66 nr=1
*Mar  1 03:04:15.595: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:04:15.619: CCBRI_Go Fr L3 pkt (Len=4) :
*Mar  1 03:04:15.619: F 1 9C 92
*Mar  1 03:04:15.623:
*Mar  1 03:04:15.627: ISDN BR0: LIF_EVENT: ces/callid 1/0x31 HOST_CONNECT
*Mar  1 03:04:15.631: BRI: enable channel B1
*Mar  1 03:04:15.631: ISDN BR0: Event: Connected to 27208196 on B1 at 64 Kb/s
*Mar  1 03:04:16.223: BR0:1 DDR: dialer protocol up
*Mar  1 03:04:17.187: %LINEPROTO-5-UPDOWN: Line protocol on Interface
BRI0:1, changed state to up
*Mar  1 03:04:20.591: %ISDN-6-CONNECT: Interface BRI0:1 is now connected to
027208196 krimson
*Mar  1 03:04:25.591: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:04:25.595: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:04:25.615: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2

kevin#show isdn status
Global ISDN Switchtype = basic-net3
ISDN BRI0 interface
dsl 0, interface ISDN Switchtype = basic-net3
Layer 1 Status:
ACTIVE
Layer 2 Status:
TEI = 66, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
I_Queue_Len 0, UI_Queue_Len 0
Layer 3 Status:
1 Active Layer 3 Call(s)
CCB:callid=31, sapi=0, ces=1, B-chan=1, calltype=DATA
Active dsl 0 CCBs = 1
The Free Channel Mask:  0x80000002
Number of L2 Discards = 0, L2 Session ID = 10
Total Allocated ISDN CCBs = 1

kevin#
*Mar  1 03:04:35.623: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:04:35.627: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:04:35.647: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:04:45.655: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:04:45.659: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:04:45.679: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:04:55.683: ISDN BR0: RX <- RRp sapi=0 tei=66 nr=2
*Mar  1 03:04:55.691: ISDN BR0: TX -> RRf sapi=0 tei=66 nr=1
*Mar  1 03:04:55.695: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:05:05.691: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:05:05.695: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:05:05.715: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:05:15.724: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:05:15.728: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:05:15.748: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:05:25.756: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:05:25.760: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:05:25.780: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:05:35.788: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:05:35.792: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:05:35.812: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:05:45.820: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:05:45.824: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:05:45.844: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:05:55.852: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:05:55.856: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:05:55.880: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:06:05.888: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:06:05.892: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:06:05.912: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:06:15.920: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=1
*Mar  1 03:06:15.924: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:06:15.944: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=2
*Mar  1 03:06:17.024: BR0:1 DDR: idle timeout
*Mar  1 03:06:17.028: BR0:1 DDR: disconnecting call
*Mar  1 03:06:17.028: ISDN BR0: Event: Hangup call to call id 0x31
*Mar  1 03:06:17.032: BRI: disable channel B1
*Mar  1 03:06:17.032: ISDN BR0: process_disconnect(): call id 0x31, call
type is DATA, b_idb 0x230B74, ces 1, cause Normal call clearing(0x10)
*Mar  1 03:06:17.040: %ISDN-6-DISCONNECT: Interface BRI0:1  disconnected
from 27208196 krimson, call lasted 122 seconds
*Mar  1 03:06:17.048: ISDN: get_isdn_service_state(): idb 0x230B74 bchan 2
is_isdn 1 Not a Pri
*Mar  1 03:06:17.052: CCBRI_Go Fr Host InPkgInfo (Len=13) :
*Mar  1 03:06:17.052: 5 0 1 0 31 3 8 1 90 8 2 80 90
*Mar  1 03:06:17.056:
*Mar  1 03:06:17.072: ISDN BR0: TX -> INFOc sapi=0 tei=66 ns=2 nr=1
i=0x08019C4508028090
*Mar  1 03:06:17.084:     DISCONNECT pd = 8  callref = 0x9C
*Mar  1 03:06:17.088:         Cause i = 0x8090 - Normal call clearing
*Mar  1 03:06:17.096: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:06:17.124: ISDN BR0: RX <- RRr sapi=0 tei=66 nr=3
*Mar  1 03:06:17.556: ISDN BR0: RX <- INFOc sapi=0 tei=66 ns=1 nr=3
i=0x08011C4D
*Mar  1 03:06:17.564:     RELEASE pd = 8  callref = 0x1C
*Mar  1 03:06:17.580: CCBRI_Go Fr L3 pkt (Len=4) :
*Mar  1 03:06:17.584: 4D 1 9C 97
*Mar  1 03:06:17.584:
*Mar  1 03:06:17.592: ISDN BR0: LIF_EVENT: ces/callid 1/0x31
HOST_DISCONNECT_ACK
*Mar  1 03:06:17.596: ISDN: get_isdn_service_state(): idb 0x230B74 bchan 2
is_isdn 1 Not a Pri
*Mar  1 03:06:17.600: ISDN BR0: HOST_DISCONNECT_ACK: call type is DATA
*Mar  1 03:06:17.604: BRI: disable channel B1
*Mar  1 03:06:17.604: %LINK-3-UPDOWN: Interface BRI0:1, changed state to
down
*Mar  1 03:06:17.612: BR0:1 DDR: disconnecting call
*Mar  1 03:06:17.616: ISDN BR0: LIF_EVENT: ces/callid 1/0x31
HOST_DISCONNECT_ACK
*Mar  1 03:06:17.620: ISDN: get_isdn_service_state(): idb 0x230B74 bchan 2
is_isdn 1 Not a Pri
*Mar  1 03:06:17.624: ISDN BR0: HOST_DISCONNECT_ACK: call type is DATA
*Mar  1 03:06:17.628: BRI: disable channel B1
*Mar  1 03:06:17.636: ISDN BR0: TX -> RRr sapi=0 tei=66 nr=2
*Mar  1 03:06:17.640: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:06:17.644: ISDN BR0: TX -> INFOc sapi=0 tei=66 ns=3 nr=2
i=0x08019C5A
*Mar  1 03:06:17.652: RELEASE_COMP pd = 8  callref = 0x9C
*Mar  1 03:06:17.660: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:06:17.684: ISDN BR0: RX <- RRr sapi=0 tei=66 nr=4
*Mar  1 03:06:18.940: %LINEPROTO-5-UPDOWN: Line protocol on Interface
BRI0:1, changed state to down
*Mar  1 03:06:27.693: ISDN BR0: TX -> RRp sapi=0 tei=66 nr=2
*Mar  1 03:06:27.697: BRI: write_sid: scp = 0, wrote = E
*Mar  1 03:06:27.717: ISDN BR0: RX <- RRf sapi=0 tei=66 nr=4
*Mar  1 03:06:32.781: ISDN BR0: RX <- DISCp c/r=1 sapi=0 tei=66
*Mar  1 03:06:32.785: %ISDN-6-LAYER2DOWN: Layer 2 for Interface BR0, TEI 66
changed to down
*Mar  1 03:06:32.793: ISDN BR0: TX -> UAf c/r=1 sapi=0 tei=66
*Mar  1 03:06:32.797: BRI: write_sid: scp = 0, wrote = E

kevin#show isdn status
Global ISDN Switchtype = basic-net3
ISDN BRI0 interface
dsl 0, interface ISDN Switchtype = basic-net3
Layer 1 Status:
ACTIVE
Layer 2 Status:
TEI = 66, Ces = 1, SAPI = 0, State = TEI_ASSIGNED  

!--- ISDN Layer 2 is disconnected

I_Queue_Len 0, UI_Queue_Len 0
Layer 3 Status:
0 Active Layer 3 Call(s)
Active dsl 0 CCBs = 0
The Free Channel Mask:  0x3
Number of L2 Discards = 0, L2 Session ID = 10
Total Allocated ISDN CCBs = 0

kevin#
*Mar  1 03:06:42.881: BRI: write_sid: scp = 0, wrote = 92
*Mar  1 03:06:42.885: BRI: write_sid: scp = 90, wrote = 93
*Mar  1 03:06:42.885: BRI0: ACTIVATED, state F2, event DI
*Mar  1 03:06:42.889: BRI: T4 timer started DEACT timer expired
*Mar  1 03:06:43.493: BRI: write_sid: scp = 0, wrote = 92
*Mar  1 03:06:43.493: BRI: write_sid: scp = 90, wrote = 93
*Mar  1 03:06:43.497: BRI: write_sid: scp = 0, wrote = 1
*Mar  1 03:06:43.497: BRI: write_sid: scp = 0, wrote = 0
*Mar  1 03:06:43.501: ISDN BR0 EVENT: isdn_sw_cstate: State = 0, Old State = 4
*Mar  1 03:06:43.505: BRI: disable channel B1
*Mar  1 03:06:43.505: BRI: disable channel B2
*Mar  1 03:06:43.509: ISDN BR0: Physical layer is IF_DOWN   
!--- ISDN Layer 1 deactivated due to no calls on BRI
*Mar  1 03:06:43.509: ISDN BR0: Shutting down ME
*Mar  1 03:06:43.513: ISDN BR0: Shutting down ISDN Layer 3

kevin#show isdn status
Global ISDN Switchtype = basic-net3
ISDN BRI0 interface
dsl 0, interface ISDN Switchtype = basic-net3
Layer 1 Status:
DEACTIVATED
Layer 2 Status:
TEI = 66, Ces = 1, SAPI = 0, State = TEI_ASSIGNED  

!--- TEI is preserved due to used configuration

I_Queue_Len 0, UI_Queue_Len 0
Layer 3 Status:
0 Active Layer 3 Call(s)
Active dsl 0 CCBs = 0
The Free Channel Mask:  0x3
Number of L2 Discards = 0, L2 Session ID = 11
Total Allocated ISDN CCBs = 0

Related Information

Revision History

Revision Publish Date Comments
1.0
09-Sep-2005
Initial Release

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