Asynchronous Transfer Mode Configuration Guide, Cisco IOS Release 15M&T
Lossless Compression and ATM Cell Switching and BITS Clocking
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Lossless Compression and ATM Cell Switching and BITS Clocking

Lossless Compression and ATM Cell Switching and BITS Clocking

Last Updated: December 4, 2012

The Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source features introduce a new compression technique in DSP firmware and add enhancements to Cisco IOS that include cell switching on ATM segmentation and reassembly (SAR), and the use of an external BITS clocking source. These features enable Cisco multiservice routers to be used to transparently groom and compress traffic in a wireless service provider network and enable a service provider to optimize the bandwidth used to backhaul the traffic from a cell site to the mobile central office for more efficient use of existing T1 and E1 lines.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Prerequisites for Lossless Compression and ATM Cell Switching and BITS Clocking

You must use a Cisco 3660 or Cisco 3745 with the following components installed:

Table 1 Supported Network Modules

Feature

Cisco 3660

Cisco 3745

Lossless compression R1

NM-HDV

NM-HDV

ATM cell switching

AIM-ATM or AIM-ATM-VOICE-30

NM-x FE2W with VWIC-x MFT-T1/E1

AIM-ATM or AIM-ATM-VOICE-30

NM-x FE2W with VWIC-x MFT-T1/E1

VWIC-x MFT-T1/E1 (on-board WIC slot)

BITS clocking

NM-HDV

NM-x FE2W with VWIC-x MFT-T1/E1

NM-HDV

NM-x FE2W with VWIC-x MFT-T1/E1

VWIC-x MFT-T1/E1 (on-board WIC slot)

Restrictions for Lossless Compression and ATM Cell Switching and BITS Clocking

  • Operations, administration, and maintenance (OAM) cell insertion is not supported on cell-switched PVCs.
  • AIM-ATM and AIM-ATM-VOICE-30 modules support a maximum of four T1/E1s. This can consist of two incoming and two outgoing, or three incoming and one outgoing T1/E1s. An IMA group cannot be split between multiple AIMs.
  • Certain combinations of AIM modules can become inoperable when installed in a Cisco 3745. This problem only affects Cisco 3745 routers manufactured before June 11, 2003. See the following link for detailed information about this problem:

http://www.cisco.com/en/US/ts/fn/200/fn25194.html

  • Voice activity detection (VAD) and echo cancellation are disabled when lossless compression is enabled.
  • Lossless compression R1 is supported for VoATM calls with AAL2 and subcell multiplexing. VoIP calls are not supported at this time.
  • ATM cell switching is limited to a maximum of 25 connections per AIM-ATM.
  • Do not configure more than 29 LLCC channels per NM-HDV module. Configuring more than 29 LLCC channels can cause unreliable operation.
  • J1 controller is not supported.
  • Traffic policing is not supported.
  • For Cisco 3660 routers with two NM-HDV modules installed, do not install the modules in the following slot combinations:
    • Slot 1 and Slot 3
    • Slot 2 and Slot 4
    • Slot 5 and Slot 6

Using these slot combinations can result in packet loss.

Information About Lossless Compression and ATM Cell Switching and BITS Clocking

The Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source features work together to groom and compress T1 and E1 traffic between cell sites and a mobile central office. These features require a Cisco 3660 or Cisco 3745 router to be installed at the base transceiver station (BTS). This cell site router performs ATM switching and compression of cell site traffic for transport to the base station controller (BSC). A Cisco MGX 8850 with AUSM and VISM-PR terminates the T1/E1 lines that carry lossless compression codec (LLCC) traffic, converting the traffic back to PCM before passing it to the BSC. The figure below shows a sample topology that makes use of the Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source features.

Figure 1 Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source Features


To configure the Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source feature, you should understand the following concepts:

Lossless Compression Codec on NM-HDV

The Lossless Compression R1 feature introduces a new compression technique in DSP firmware and the VISM card-- the lossless compression codec (LLCC). LLCC operates in a similar fashion to the existing clear channel codec: the decoded 64kbps PCM stream is a bit-exact replica of the PCM stream provided on the TDM side of the encoding DSP. However, rather than simply packetizing the PCM stream, the LLCC encoder applies a lossless data compression scheme. This results in a net reduction in the data transmission rate, yielding a reduction in the packet transmission rate.

ATM Cell Switching on AIM-ATM and AIM-ATM-VOICE-30

The Cisco ATM Cell Switching feature enables the router to perform cell switching between two ATM connections on AIM-ATM and AIM-ATM-VOICE-30 cards, giving the router the ability to receive ATM traffic from the BTS and backhaul it to the mobile central office.

BITS Clocking on the Cisco 3660 and Cisco 3745

BITS (Building Integrated Timing Supply) network clocking enables a Cisco 3660 or Cisco 3745 router to derive network timing from the central office. BITS must be configured on the cell site router to support this feature.

How to Configure Lossless Compression and ATM Cell Switching and BITS Clocking

The instructions that follow refer to the sample configuration shown in the figure below. With this configuration, the cell site router supports three E1 connections to the BTS. Compressed cellular traffic is transported to the BSC (by way of the Cisco MGX 8850) over the E1 1/0 and E1 1/1 interfaces. Additionally, BITS clocking is derived from E1 1/1.

Figure 2 Sample Configuration


Configuring the Cell Site Router for BITS Clocking

BITS clocking enables the router at a cell site to derive timing from the mobile central office. BITS clocking ensures that data flows to a single network clock source, preventing mismatches and data slips in traffic between the BTS and the BSC. The procedure that follows configures the AIM to receive BITS clocking from E1 1/1 controller.

To configure the cell site router for BITS clocking, perform the steps in this section.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    network-clock-participate slot number

4.    network-clock-select priority slot number

5.    controller t1 | e1 slot/port

6.    clock source {line [primary | bits] | internal}


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode. Enter your password when prompted.

 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
network-clock-participate slot number


Example:

Router(config)# network-clock-participate slot 1

 

Allows the network module in the specified slot to use the network clock for its timing.

 
Step 4
network-clock-select priority slot number


Example:

Router(config)# network-clock-select 1 E1 1/1

 

Specifies a port to be used as a timing source for the network clock, and the priority level for the use of that port. The source that is given the highest priority is used first; if it becomes unavailable, the source with the second-highest priority is used, and so forth.

 
Step 5
controller t1 | e1 slot/port


Example:

Router(config)# controller e1 1/1

 

Enters controller configuration mode for the selected T1 or E1.

 
Step 6
clock source {line [primary | bits] | internal}


Example:

Router(config-controller)# clock source line bits

 

Specifies that the clock is generated from the T1 or E1 BITS source.

 

Configuring ATM Cell Switching

The procedure that follows configures the cell site router to switch ATM traffic with the Cisco MGX 8850 at the BSC. This procedure configures ATM switching between E1 3/0 and E1 1/0, using the AIM installed in Slot 1.

To configure ATM cell switching, perform the steps in this section.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    network-clock-participate slot number

4.    network-clock-participate slot number

5.    network-clock-participate aim number

6.    controller t1 | e1 slot/port

7.    mode atm aim aim-slot

8.    controller t1 | e1 slot/port

9.    mode atm aim aim-slot

10.    interface atm interface-number / subinterface-number

11.    pvc vpi / vci l2transport

12.    interface atm interface-number / subinterface-number

13.    pvc vpi / vci l2transport

14.    connect id atm slot . port-1 atm slot . port-2


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode. Enter your password when prompted.

 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
network-clock-participate slot number


Example:

Router(config)# network-clock-participate slot 1

 

Enables the network module in the specified slot to use the network clock for its timing.

 
Step 4
network-clock-participate slot number


Example:

Router(config)# network-clock-participate slot 3

 

Enables the network module in the specified slot to use the network clock for its timing.

 
Step 5
network-clock-participate aim number


Example:

Router(config)# network-clock-participate aim 0

 

Specifies that the AIM in Slot 0 will derive clocking from the network source.

 
Step 6
controller t1 | e1 slot/port


Example:

Router(config)# controller e1 1/0

 

Enters controller configuration mode for the selected T1 or E1.

 
Step 7
mode atm aim aim-slot


Example:

Router(config-controller)# mode atm aim 0

 

Sets the mode of the T1 or E1 controller in AIM Slot 0.

 
Step 8
controller t1 | e1 slot/port


Example:

Router(config)# controller e1 3/0

 

Enters controller configuration mode for the selected T1 or E1.

 
Step 9
mode atm aim aim-slot


Example:

Router(config-controller)# mode atm aim 0

 

Sets the mode of the T1 or E1 controller in AIM Slot 0.

 
Step 10
interface atm interface-number / subinterface-number


Example:

Router(config) # interface atm 1/0

 

Enters configuration mode for the selected ATM interface.

 
Step 11
pvc vpi / vci l2transport


Example:

Router(config-if)# pvc 10/110 l2transport

 

Creates a PVC for the virtual path identifier (VPI) and virtual channel identifier (VCI) and specifies that the PVC is switched, not terminated.

 
Step 12
interface atm interface-number / subinterface-number


Example:

Router (config) # interface atm 3/0

 

Enters configuration mode for the selected ATM interface.

 
Step 13
pvc vpi / vci l2transport


Example:

Router(config-if)# pvc 30/130 l2transport

 

Creates a PVC for the VPI and VCI and specifies that the PVC is switched.

 
Step 14
connect id atm slot . port-1 atm slot . port-2


Example:



Example:

Router(config)# connect Switched-Conn atm 1/0 10/110 atm 3/0 30/130

 

Defines connections between T1 or E1 controller ports and the ATM interface.

 

Configuring the Lossless Compression Codec

The procedure that follows configures an LLCC voice channel on E1 4/0 and sends it over the ATM network using E1 1/0 and the AIM installed in Slot 1.

To configure the lossless compression codec, perform the steps in this section.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    network-clock-participate slot number

4.    network-clock-participate slot number

5.    network-clock-participate aim number

6.    voice service {pots | voatm | vofr | voip}

7.    session protocol aal2

8.    subcell-mux

9.    codec aal2-profile custom profile-number codec

10.    controller t1 | e1 slot/port

11.    mode atm aim aim-slot

12.    controller t1 | e1 slot/port

13.    ds0-group ds0-group-number timeslots timeslot-list type signaling method

14.    interface atm interface-number /subinterface-number

15.    pvc vpi /vci

16.    vbr-rt peak-rate average-rate burst

17.    encapsulation aal2

18.    dial-peer voice tag voatm

19.    destination-pattern string

20.    session protocol aal2-trunk

21.    session target interface pvc vpi/vci

22.    signal-type cas | cept | ext-signal | transparent

23.    codec aal2-profile custom profile-number codec

24.    voice-port {slot-number /subunit-number /port | slot /port :ds0-group-no }

25.    playout-delay {fax | maximum | nominal} milliseconds

26.    connection {plar | tie-line | plar-opx} digits | {trunk digits [answer-mode]}


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode. Enter your password when prompted.

 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
network-clock-participate slot number


Example:

Router(config)# network-clock-participate slot 1

 

Enables the network module in the specified slot to use the network clock for its timing.

 
Step 4
network-clock-participate slot number


Example:

Router(config)# network-clock-participate slot 4

 

Enables the network module in the specified slot to use the network clock for its timing.

 
Step 5
network-clock-participate aim number


Example:

Router(config)# network-clock-participate aim 0

 

Specifies that the AIM in Slot 0 will derive clocking from the network source.

 
Step 6
voice service {pots | voatm | vofr | voip}


Example:

Router(config)# voice service voatm

 

Enters voice service configuration mode and specifies VoATM as the encapsulation type.

 
Step 7
session protocol aal2


Example:

Router( config-voi-serv)# session protocol aal2

 

Enters voice-service-session configuration mode and specifies ATM adaptation layer 2 (AAL2) trunking.

 
Step 8
subcell-mux


Example:

Router(conf-voi-serv-sess)# subcell-mux

 

Enables AAL2 common part sublayer (CPS) subcell multiplexing.

 
Step 9
codec aal2-profile custom profile-number codec


Example:

Router# codec aal2-profile custom 51 0 0 llcc 40 0 15

 

Sets the codec profile for the DSP on a per-call basis and specifies the lossless compression codec.

 
Step 10
controller t1 | e1 slot/port


Example:

Router(config)# controller e1 1/0

 

Enters controller configuration mode for the selected T1 or E1.

 
Step 11
mode atm aim aim-slot


Example:

Router(config-controller)# mode atm aim 0

 

Sets the mode of the T1 or E1 controller in AIM Slot 0.

 
Step 12
controller t1 | e1 slot/port


Example:

Router(config)# controller e1 4/0

 

Enters controller configuration mode for the selected T1 or E1.

 
Step 13
ds0-group ds0-group-number timeslots timeslot-list type signaling method


Example:

Router(config-controller)# ds0-group 0 timeslots 1 type ext-sig

 

Specifies the DS0 time slots that make up a logical voice port on a T1 or E1 controller and specifies the signaling type used by the router.

 
Step 14
interface atm interface-number /subinterface-number


Example:

Router(config) # interface atm 1/0

 

Enters configuration mode for the selected ATM interface.

 
Step 15
pvc vpi /vci


Example:

Router(config-if-atm)# pvc 10/110

 

Enters configuration mode for the selected PVC.

 
Step 16
vbr-rt peak-rate average-rate burst


Example:

Router(config-if-atm-pvc)# vbr-rt 1920 1920 255

 

Configures real-time variable bit rate (VBR) for VoATM voice connections.

 
Step 17
encapsulation aal2


Example:

Router(config-if-atm-pvc)# encapsulation aal2

 

Configures the encapsulation type for the ATM virtual circuit.

 
Step 18
dial-peer voice tag voatm


Example:

Router(config)# dial-peer voice 1001 voatm

 

Defines a dial-peer and specifies the method of voice encapsulation as VoATM.

 
Step 19
destination-pattern string


Example:

Router(config-dial-peer)# destination-pattern 1001

 

Specifies the prefix to be used by the dial peer.

 
Step 20
session protocol aal2-trunk


Example:

Router(config-dial-peer)# session protocol aal2-trunk

 

Specifies the dial peer uses AAL2 nonswitched trunk session protocol.

 
Step 21
session target interface pvc vpi/vci


Example:

Router(config-dial-peer)# session target atm 1/0 pvc 10/100 9

 

Specifies the network-specific address for the VoATM dial peer.

 
Step 22
signal-type cas | cept | ext-signal | transparent


Example:

Router(config-dial-peer)# signal-type ext-signal

 

Specifies that external signaling is used when connecting to the dial peer. The DSP does not generate any signaling frames.

 
Step 23
codec aal2-profile custom profile-number codec


Example:

Router(config-dial-peer)# codec aal2-profile custom 51 llcc

 

Sets the codec profile for the DSP on a per-call basis and specifies the lossless compression codec.

 
Step 24
voice-port {slot-number /subunit-number /port | slot /port :ds0-group-no }


Example:

Router(config)# voice-port 2/0:0

 

Enters voice-port configuration mode.

 
Step 25
playout-delay {fax | maximum | nominal} milliseconds


Example:

Router(config-voice-port)# playout-delay nominal 25

 

Tunes the playout buffer to accommodate packet jitter caused by switches in the WAN. The nominal keyword specifies the initial (and minimum allowed) delay time that the DSP inserts before playing out voice packets, in milliseconds.

 
Step 26
connection {plar | tie-line | plar-opx} digits | {trunk digits [answer-mode]}


Example:

Router(config-voice-port)# connection trunk 1001

 

Associates this voice-port to destination-pattern 1001.

 
What to Do Next


Note


To ensure that the voice-port configuration takes affect, issue the shutdown command, followed by no shutdown to enable it again.

Disabling Connection Admission Control

Connection admission control (CAC) is a set of actions taken by each ATM switch during connection setup to determine whether the requested QoS will violate the QoS guarantees for established connections. CAC reserves bandwidth for voice calls, however, the bandwidth required when LLCC is used is dynamic and usually less than what is generally reserved by CAC. Disabling CAC may help in better utilization of bandwidth when LLCC is used.

To disable CAC, perform the steps in this section.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface atm interface-number /subinterface-number

4.    pvc vpi /vci

5.    cac_off


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode. Enter your password when prompted.

 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
interface atm interface-number /subinterface-number


Example:

Router(config) # interface atm 1/0

 

Enters configuration mode for the selected ATM interface.

 
Step 4
pvc vpi /vci


Example:

Router(config-if-atm)# pvc 10/110

 

Enters configuration mode for the selected PVC.

 
Step 5
cac_off


Example:

Router# (config-if-atm-vc)# cac_off

 

Disables call admission control.

 

Verifying Lossless Compression and ATM Cell Switching and BITS Clocking

To verify the confituration use the following commands.

  • show connection all
  • show voice dsp
  • show voice call port-id
  • show voice trunk supervisory summary
  • show interfaces

show connection all

The following example shows output from the show connection allcommand. In this example, Switched-Conn is a cell-switched connection established between PVC 10/110 and PVC 30/130, which are configured under ATM1/0 and ATM3/0 respectively.

Router# show connection all
ID    Name             Segment 1             Segment 2           State
========================================================================
3     V-100-700        E1 1/0(VOICE) 00      DSP 07/00/00        UP
4     V-120-700        E1 1/2(VOICE) 00      DSP 07/00/00        UP
5     Switched-Conn    ATM1/0 10/110         ATM3/0 30/130       UP

The show connection all command displays the state of Switched-Conn. If it is in the UP state, then it means the ATM cell switching connection is operational.

show voice dsp

The following example shows output from the show voice dsp command:

Router# show voice dsp
DSP  DSP             DSPWARE CURR  BOOT                         PAK  TX/RX
TYPE NUM CH CODEC    VERSION STATE STATE   RST AI VOICEPORT TS ABORT PACK COUNT
==== === == ======== ======= ===== ======= === == ========= == ===== ==========
C549 000 04 llcc     4.3.392 busy  idle         0 4/0:0     04     0 1752/1752

The show voice dsp command shows if the LLCC codec has been applied to the voice port. Additionally, the TX/RX COUNT indicates if packet exchange is occurring. If LLCC is operational, then TX/RX COUNT will display similar values.

show voice call port-id

The show voice callcommand gives detailed information about the lossless compression codec. The following example shows output from the show voice call command:


Note


The show voice call command has a limitation that causes it to display invalid values. To ensure that accurate values are reported, invoke this command twice and look at the second output.
Router# show voice call 4/0:0
4/0:0 1
      vtsp level 0 state = S_CONNECTvpm level 1 state = S_TRUNKED
vpm level 0 state = S_UP
lossless compression summary:
    average compression ratio since reset       = 50
    current compression ratio                   = 50
    max buffer size (ms)                        = 41
    nominal buffer size (ms)                    = 25
    current buffer size (ms)                    = 26
    total encoder input frame count             = 5534
    total encoder output frame count            = 2767
    encoded tx front-end compressed frame count = 2767
    encoded tx back-end compressed frame count  = 0
    encoded tx frame count (no compression)     = 0
    underflow error count                       = 0
    overflow error count                        = 0
    decode error count                          = 0
    tx signalling frame count                   = 11
    rx signalling frame count                   = 10
    rx bad checksum frame count                 = 0
    rx good checksum frame count                = 2777

show voice trunk supervisory summary

The following example shows output from the show voice trunk supervisory summary command:

Router# show voice trunk supervisory summary
SLOW SCAN
4/0:0(1) : state : TRUNK_SC_CCS_CONNECT, master

show interfaces

The following example shows output from the show interfaces command:

Router# show interfaces atm1/0
ATM1/0 is up, line protocol is up 
  Hardware is ATM AIM E1
  MTU 4470 bytes, sub MTU 4470, BW 1920 Kbit, DLY 20000 usec, 
     reliability 0/255, txload 1/255, rxload 1/255
  Encapsulation ATM, loopback not set
  Encapsulation(s): AAL5 
  255 maximum active VCs, 256 VCs per VP, 0 current VCCs
  VC Auto Creation Disabled.
  VC idle disconnect time: 300 seconds
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: Per VC Queueing
  30 second input rate 0 bits/sec, 0 packets/sec
  30 second output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 output buffer failures, 0 output buffers swapped out

Additional References

The following sections provide references related to the Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source feature.

Related Documents

Related Topic

Document Title

Configuring voice features

Cisco IOS Voice Configuration Library, Release 12.4T

Configuring ATM advanced integration modules

"AIM-ATM and AIM-ATM-VOICE-30 on the Cisco 2600 Series, Cisco 3660, and Cisco 3700 Series" feature module

Configuring high-density voice network modules

"Digital E1 Packet Voice Trunk Network Module Interfaces" feature module

Standards

Standard

Title

None

--

MIBs

MIB

MIBs Link

CISCO-VOICE-COMMON-DIAL-CONTROL-MIB

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

RFCs

RFC

Title

No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.

--

Technical Assistance

Description

Link

The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

http://www.cisco.com/techsupport

Feature Information for Lossless Compression and ATM Cell Switching and BITS Clocking

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 2 Feature Information for Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source

Feature Name

Releases

Feature Information

Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source

12.3(4)XD 12.3(7)T

The Lossless Compression R1, ATM Cell Switching, and External BITS Clocking Source features introduce a new compression technique in DSP firmware and add enhancements to Cisco IOS that include cell switching on ATM segmentation and reassembly (SAR), and the use of an external BITS clocking source. These features enable Cisco multiservice routers to be used to transparently groom and compress traffic in a wireless service provider network and enable a service provider to optimize the bandwidth used to backhaul the traffic from a cell site to the mobile central office for more efficient use of existing T1 and E1 lines.

The following commands were introduced or modified: cac_off, clock source (T1/E1 controller), codec aal2-profile, connect (atm).

Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: www.cisco.com/go/trademarks. Third-party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1110R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

© 2012 Cisco Systems, Inc. All rights reserved.