Video QAM Replication

The Video QAM replication feature allows video carriers to be replicated to support service group alignment between DOCSIS and Video service groups.

Contents

QAM Replication

The QAM replication feature allows duplication of content on multiple QAM carriers. This feature is internal to the cBR-8 and replaces the need for external splitters, allowing content to be replicated across multiple ports on a line card.

Information About Replication

  • Multiple Ports: Multiple ports in a Service Distribution Group (SDG) replicate all QAMs from the Virtual Carrier Group (VCG) to output port listed in the same SDG.

  • Unicast: Unicast (Video on Demand) services cannot be replicated across line cards.

Overview of QAM Replication

Video on Demand (VoD) or unicast services cannot be replicated across line cards. You can accomplish replication by adding more than one RF port to an SDG. This feature works for the SDG regardless of whether the video sessions are table-based or session-based.

Replication also applies to the QAM PHY parameters. Hence, the QAM PHY parameters like frequency, annex, and symbol rate of the replicated QAM carrier are the same as the QAM PHY parameters on the pilot QAM carrier.

QAM replication is achieved in two ways: software and hardware. The line card performs the hardware QAM replication. Each line card has the capability to replicate an output QAM (Pilot QAM) from one port to another output QAM (Replicate QAM) on another port.


Note

QAM replication in the same port is not supported.

The service-distribution-group construct is used to perform replication. Hardware replication is supported when the replication of individual QAM Carriers is limited to the same line card.

The bind-vcg construct, which is used to determine the physical QAMs to be replicated, is analogous to combiner and splitter combination. The RF ports combine all the QAMs routed to them. Then, one or more inputs are split to one or more RF output ports.

Benefits of QAM Replication

QAM replication reduces the need for external HFC components like splitters and combiners in the RF plant.

The figure below illustrates the bind operation that replaces a combiner and a splitter and performs replication on multiple ports that are assigned to an SDG.

Prerequisites for Replication

The controller type for the slot/bay/port used for the SDG should be set as 'VIDEO'. The errors corresponding to the incorrect controller type used in the SDG appear during the bind operation.

Perform the following steps to set the controller type: 

configure terminal
controller Integrated-Cable slot/bay/port
rf-channel start-channel – end-channel
type VIDEO
start-frequency frequency
rf-output normal
power-adjust number
qam-profile qam-profile number

Restrictions for QAM Replication

  • Hardware can support QAM replication only within the same line card.
  • The output of a source QAM in any port can be replicated to only one QAM in another port. Replication within the same port is not supported.
  • The current line card has a maximum of eight ports. Hence, for each line card a pilot QAM can have up to seven replicates (one on each port).
  • Standard routing protocols prohibit routing of unicast traffic (VOD) to multiple destinations (across line cards).

Configuring Replication for Table-Based or Session-Based Video

Replication is configured within the SDG by adding a set of RF ports to the same SDG. To configure replication you must choose the Pilot QAM carriers, a set of QAM carriers belonging to a RF port. The Pilot QAM carriers are denoted by the first RF port added under SDG. The rest of RF ports, which carry the replicated content, are specified within this SDG.

Choose the QAM carriers, which carry the content to be replicated, by configuring Virtual Carrier Group (VCG) and specifying the number of QAM channels that are replicated in each RF port. When the pilot QAM carrier is removed, one of the remaining replicated QAM carriers is automatically chosen as pilot QAM carrier.

To configure the replication, complete the following procedure: 

configure terminal
cable video
service-distribution-group service distribution group name 
rf-port integrated-cable slot/bay/port
rf-port integrated-cable slot/bay/port
virtual-carrier-group vcg_replication id number
virtual-edge-input-ip ip-address vrf vrf-name input-port-number number
rf-channel n-m tsid n-m output-port-number n-m
bind-vcg
vcg vcg_replication sdg sdg_replication

Verifying Replication of Table Based Video Sessions

To verify the replication information including the replication group ID, pilot or replicant, and the associated status, use the show cable card slot/bayqam-repl group command as shown in the example below: 

Router#show cable card 7/0 qam-repl group
-----------------------------------------------------------------
Grp Slot Chan QAM Grp   Chan
ID Grp cnt type State List
ID  [port:chan state role]
U:Up   P:Pilot
D:Down R:Replicant

-----------------------------------------------------------------
57344 0    4  VID   U   0:21  UP   1:21  UR   2:21  UR   3:21  UR

57345 1    4  VID   U   0:22  UP   1:22  UR   2:22  UR   3:22  UR

57346 2    4  VID   U   0:23  UP   1:23  UR   2:23  UR   3:23  UR

57347 3    4  VID   U   0:24  UP   1:24  UR   2:24  UR   3:24  UR

57348 4    4  VID   U   0:25  UP   1:25  UR   2:25  UR   3:25  UR

57349 5    4  VID   U   0:26  UP   1:26  UR   2:26  UR   3:26  UR

57350 6    4  VID   U   0:27  UP   1:27  UR   2:27  UR   3:27  UR

57351 7    4  VID   U   0:28  UP   1:28  UR   2:28  UR   3:28  UR

57352 8    4  VID   U   0:29  UP   1:29  UR   2:29  UR   3:29  UR

57353 9    4  VID   U   0:30  UP   1:30  UR   2:30  UR   3:30  UR

57354 10   4  VID   U   0:31  UP   1:31  UR   2:31  UR   3:31  UR


-----------------------------------------------------------------
Total number of Replication groups on slot 7/0: 11

To verify the sessions on the pilot QAM carrier, use the show cable video session logical-edge-device id number command as shown in the example below: 

Router#show cable video session logical-edge-device id 1
Total Sessions = 22


Session    Output     Streaming   Session  Destination     UDP        Output      Input   Output    Input    Output   Encrypt  Encrypt   Session
Id         Port       Type        Type      Port           Program    State       State   Bitrate   Bitrate  Type     Status     Name
------------------------------------------------------------------------------------------------------------------------------------------------------
1048598    21         Remap       UDP      172.16.0.1     49152 32    ACTIVE-PSI  ON     1104548  1088424    CLEAR    -         bago_tbv.1.21.49152
1048599    21         Remap       UDP      172.16.0.1     49153 33    ACTIVE-PSI  ON     1104482  1088424    CLEAR    -         bago_tbv.1.21.49153
1048600    22         Remap       UDP      172.16.0.1     49154 34    ACTIVE-PSI  ON     1104922  1090656    CLEAR    -         bago_tbv.1.22.49154
1048601    22         Remap       UDP      172.16.0.1     49155 35    ACTIVE-PSI  ON     1105033  1090534    CLEAR    -         bago_tbv.1.22.49155
1048602    23         Remap       UDP      172.16.0.1     49156 36    ACTIVE-PSI  ON     1114332  1092488    CLEAR    -         bago_tbv.1.23.49156
1048603    23         Remap       UDP      172.16.0.1     49157 37    ACTIVE-PSI  ON     1104353  1092488    CLEAR    -

Configuration Examples

The following example configures replication across four RF ports on line card 7/0: 

configure terminal
cable video
service-distribution-group sdg replication id 1
rf-port integrated-cable 7/0/0 
rf-port integrated-cable 7/0/1 
rf-port integrated-cable 7/0/2 
rf-port integrated-cable 7/0/3 
virtual-carrier-group vcg_replication id  1
virtual-edge-input-ip 172.31.1.1 vrf vrf-name input-port-number 1 
rf-channel 21-31 tsid 21-31 output-port-number 21-31
bind-vcg
vcg vcg_replication sdg sdg_replication

Feature Information for Replication

Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http:/​/​www.cisco.com/​go/​cfn. An account on Cisco.com is not required.


Note

The table below 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.

Table 1 Feature Information for Replication

Feature Name

Releases

Feature Information

Replication

Cisco IOS-XE Release 16.4.1

This feature was integrated into Cisco IOS-XE Release 16.4.1 on the Cisco cBR Series Converged Broadband Routers.