- Cable Modem Upstream RF Adaptation
- Configuring Downstream Cable Interface Features on the Cisco CMTS Routers
- Configuring Upstream Cable Interface Features on the Cisco CMTS Routers
- Cable Modem Steering on the Cisco CMTS Routers
- DOCSIS 2.0 A-TDMA Modulation Profiles for the Cisco CMTS Routers
- DOCSIS 3.0 Downstream Bonding for Bronze Certification
- Downstream Channel ID Assignment on the Cisco CMTS Routers
- Downstream Resiliency Bonding Group
- IGMP-Triggered Dynamic Channel Change Load Balancing for DOCSIS 2.0 Cable Modems
- IGMP-Triggered VDOC Broadcast Support on the Cisco CMTS Routers
- Load Balancing, Dynamic Channel Change, and Dynamic Bonding Change on the Cisco CMTS Routers
- M-CMTS DEPI Control Plane
- Restricted/General Load Balancing and Narrowband Dynamic Bandwidth Sharing with Downstream Dynamic Load Balancing
- RSVP-Based Video on Demand Support Over DOCSIS
- S-CDMA and Logical Channel Support on the Cisco CMTS Routers
- Spectrum Management and Advanced Spectrum Management for the Cisco CMTS
- Support for Extended Upstream Frequency Ranges
- Upstream Bonding Support for D-PON on the Cisco CMTS Routers
- Upstream Channel Bonding
- Upstream Scheduler Mode for the Cisco CMTS Routers
- Upstream Utilization Optimization on the Cisco CMTS Routers
- Wideband Modem Resiliency
- Downgrading Channel Bonding in Battery Backup Mode
- Index
- Prerequisites for Configuring Downstream Cable Interfaces on the Cisco CMTS Routers
- Activating Downstream Cable Address Resolution Protocol Requests
- Activating Downstream Ports
- Assigning the Downstream Channel ID
- Traffic Shaping
- Configuring Downstream Rate Limiting and Traffic Shaping
- Setting the Downstream Helper Address
- Setting the Downstream Interleave Depth
- Setting the Downstream Modulation
- Setting the Downstream MPEG Framing Format
- Setting Downstream Traffic Shaping
- Activating Host-to-Host Communication (Proxy ARP)
- Activating Packet Intercept Capabilities
- Configuring Payload Header Suppression and Restoration
- Setting Optional Broadcast and Cable IP Multicast Echo
- Cable Interface Configuration Examples
- Example: Subinterface Configuration
- Example: Cable Interface Bundling
- Example: Subinterface Definition on Bundle Master
- Example: Cable Interface Bundle Master Configuration
- Example: PE Router Configuration
- Example: Router Configuration
- Example: Configuring BGP Routing Sessions
- Example: Configuring PE-to-PE Routing Sessions
- Example: Configuring BGP PE-to-CE Routing Sessions
- Example: Configuring RIP PE-to-CE Routing Sessions
- Example: Configuring Static Route PE-to-CE Routing Sessions
Configuring Downstream Cable Interface Features on the Cisco CMTS Routers
First Published: February 14, 2008
Last Updated: May 12, 2009
 Note | Cisco IOS Release 12.2(33)SCA integrates support for this feature on the Cisco CMTS routers. This feature is also supported in Cisco IOS Release 12.3BC, and this document contains information that references many legacy documents related to Cisco IOS 12.3BC. In general, any references to Cisco IOS Release 12.3BC also apply to Cisco IOS Release 12.2SC. |
The cable interface in the Cisco universal broadband routers serves as the cable TV radio frequency (RF) interface, supporting downstream and upstream signals. The downstream signal is output as an intermediate-frequency (IF) signal suitable for use with an external upconverter. Your cable plant, combined with your planned and installed subscriber base, service offering, and external network connections, determines the combination of cable interfaces, network uplink line cards, and other components that you should use.
The Cisco IOS software command-line interface (CLI) can be used to configure the Cisco cable interface line card for correct operation on the hybrid fiber-coaxial (HFC) cable network. This chapter provides a configuration summary for the various downstream cable interface features available on a Cisco CMTS router. Details about some of these features can be found in other chapters of this book.
Note | The configuration commands and examples in this chapter may show slot numbering or references to either Cisco uBR7200 series or Cisco uBR10012 Universal Broadband Routers. However, the features can be configured on either platform. Use the slot numbering appropriate for your CMTS router configuration. |
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see 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 document.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to http://tools.cisco.com/ITDIT/CFN/. An account on http://www.cisco.com/ is not required.
Contents
- Prerequisites for Configuring Downstream Cable Interfaces on the Cisco CMTS Routers
- Activating Downstream Cable Address Resolution Protocol Requests
- Activating Downstream Ports
- Assigning the Downstream Channel ID
- Traffic Shaping
- Configuring Downstream Rate Limiting and Traffic Shaping
- Setting the Downstream Helper Address
- Setting the Downstream Interleave Depth
- Setting the Downstream Modulation
- Setting the Downstream MPEG Framing Format
- Setting Downstream Traffic Shaping
- Activating Host-to-Host Communication (Proxy ARP)
- Activating Packet Intercept Capabilities
- Configuring Payload Header Suppression and Restoration
- Setting Optional Broadcast and Cable IP Multicast Echo
- Cable Interface Configuration Examples
Prerequisites for Configuring Downstream Cable Interfaces on the Cisco CMTS Routers
The configuration of downstream cable interface features is supported on the Cisco CMTS routers in Cisco IOS Release 12.3BC and 12.2SC. The table below shows the hardware compatibility prerequisites for this feature.
|
CMTS Platform |
Processor Engine |
Cable Interface Cards |
|---|---|---|
|
Cisco uBR10012 Universal Broadband Router |
Cisco IOS Release 12.2(33)SCA Cisco IOS Release 12.2(33)SCH and later releases |
Cisco IOS Release 12.2(33)SCA |
|
Cisco uBR7246VXR Universal Broadband Router |
Cisco IOS Release 12.2(33)SCA
|
Cisco IOS Release 12.2(33)SCA
|
|
Cisco uBR7225VXR Universal Broadband Router |
Cisco IOS Release 12.2(33)SCA
|
Cisco IOS Release 12.2(33)SCA
|
Note | In most applications, default values for the commands used in these configuration steps are adequate to configure the Cisco CMTS router. You do not need to specify individual parameters unless you want to deviate from system defaults. |
Activating Downstream Cable Address Resolution Protocol Requests
This configuration is required. Address Resolution Protocol (ARP) is an Internet protocol used to map IP addresses to MAC addresses on computers and other equipment installed in a network. You must activate ARP requests on the cable interface so that the Cisco uBR10000 series CMTS can perform IP address resolution on the downstream path.
Note | The default values for the commands used in this configuration step are adequate in most cases to configure the Cisco uBR7200 series CMTS. |
no cable arp
.
Router# more system:running-config Building configuration... Current configuration: ! interface cable5/0 ip address 1.1.1.1 255.255.255.0 no keepalive no cable arp cable downstream annex B cable downstream modulation 64qam cable downstream interleave-depth 32 cable downstream symbol-rate 5056941 cable upstream 0 frequency 15008000 no cable upstream 0 shutdown
 Tip | If you are having difficulty with verification, verify that you entered the correct port and cable interface line card slot number when you activated ARP and when you entered the show interface cable command. |
Activating Downstream Ports
To activate a downstream port on a Cisco uBR7200 series cable interface card for digital data transmissions over the HFC network, complete the steps in the following table.
To determine if the downstream carrier is active (up), enter the show controllers cable command for the downstream port that you just configured. For National Television Standards Committee (NTSC) 6 MHz operations, see the following example:
Router# show controllers cable5/0 downstream Cable5/0 Downstream is up Frequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 Msps FEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4
Assigning the Downstream Channel ID
To assign a numeric channel ID to the downstream port on the Cisco cable interface line card, use the following command in cable interface configuration mode.
Router(config-if)# cable downstream channel-id id
Note | For Cisco IOS Release 12.2(33)SCB and later releases, the acceptable range is 1 to 255 (0 is reserved for network management) and for releases prior to Cisco IOS Release 12.2(33)SCB, the acceptable range is 0 to 255. |
Note | cable downstream frequency 54000000-1000000000 broadcast frequency - h |
These commands are used in instances where you want to send multiple downstream frequencies to a single region that contains CMs that can connect only to upstream ports on the same cable interface line card. You must configure unique channel IDs for each downstream that any CM is capable of receiving. The downstream frequency setting must match the setting on the upconverter.
 Caution | After defining unique downstream IDs, test the CMs for correct operation. Cisco recommends that when using this feature, you re-test each subsequent software release of CM code to verify correct operation and to ensure reasonable acquisition time for new installations. Failure to use these commands in conjunction or to test the involved CMs can result in customer service outages of indefinite duration. |
Verifying the Downstream Channel ID
To verify the downstream channel ID, enter the show controllers cable command for the downstream port you have just configured. See the following example:
Router# show controllers cable5/0 downstream Cable5/0 Downstream is up Frequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 Msps FEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4 Downstream channel ID: 1
Traffic Shaping
Traffic shaping basically uses queues to limit data surges that can congest a network. The data is buffered and then sent into the network in regulated amounts to ensure that the traffic fits within the expected traffic envelope for the particular connection.
Traffic shaping reduces the chance that information must be retransmitted to hosts on the cable plant. When cable modems (CMs) have rate limits established, the CMTS typically drops data packets to enforce the rate limit. Dropping packets from the requesting CM causes the host sending the information to retransmit its information, which wastes bandwidth on the network. If both hosts sending and requesting information are on the cable plant, the upstream bandwidth is wasted as well.
Traffic shaping allows the CMTS to perform upstream and downstream rate limiting on the DOCSIS upstream and downstream channels. Rate limiting restricts the data rate to and from a CM; the MAC scheduler supports traffic-shaping capabilities for downstream and upstream traffic. Rate limiting ensures that no single CM consumes all of the channel bandwidth and allows a CMTS administrator to configure different maximum data rates for different subscribers. Subscribers requiring higher sustained rates and willing to pay for higher rates can be configured with higher sustained rate limits in their CM DOCSIS configuration file over regular subscribers, who pay less and get lower rate limits.
Each time a packet belonging to a flow is transmitted on an output channel, the token-bucket policer function checks the rate limit status of the flow, passing the following parameters:
- Token bucket maximum sustained rate in bits per millisecond.
- Token bucket depth (maximum transmit burst) in bits.
- Length of current packet to be sent in bits.
- Pointer to the flow’s token bucket.
- Pointer to the flow’s token bucket last update time stamp.
- Variable to return the milliseconds buffering delay in case the packet needs to be shaped.
- Maximum buffering delay that the subsequent traffic shaper can handle in milliseconds.
Every flow has its own shaping buffer where rate-exceeded packets are typically held back in first-in/first-out (FIFO) order for later releases transmission.
Tip | Token bucket policing with shaping is the per-upstream default rate limiting setting at the CMTS. Shaping can be enabled or disabled for the token-bucket algorithm. |
Downstream Traffic Shaping
The CMTS supports basic downstream traffic shaping by effecting data rate limiting on a per-modem basis. A downstream traffic shaping feature called downstream rate limiting with type of service (ToS) bits extends that capability by allowing the CMTS administrator to configure the ToS byte to calculate the data rate for a specified flow.
Downstream rate limiting with ToS bits enables you to partition downstream traffic for a CM into multiple classes of service and multiple data rates by using the three precedence bits in the ToS byte in the IP header to specify a class of service assignment for each packet. Those packets with the precedence bit set in the ToS field are given higher priority. Using the ToS byte, you can calculate the data rate for a specified flow, in addition to the data rate configured on a per-CM basis. By specifying a maximum data rate for a particular ToS, you can override the common maximum downstream data rate.
The administrator can override the maximum common downstream data rate limits by configuring the ToS byte.
Packets that contain ToS bytes that have not been configured for downstream data rates continue to use the common data rate limits.
Configuring Downstream Rate Limiting and Traffic Shaping
To configure downstream traffic shaping, use the following command in cable interface configuration mode.
|
Command |
Purpose |
|---|---|
Router(config-if)# [no] cable downstream rate-limit token-bucket [shaping] weighted-discard [expwt <n>] |
Enables or disables rate limiting and traffic shaping on the downstream of a cable interface. |
Note | Using Cisco IOS Release 12.0(5)T1 or higher, the software adds downstream calendar queuing routines and grant shaping application of the calendar queues. |
Note | Effective with Cisco IOS Release 12.2(33)SCF, the cable downstream rate-limit command is not supported for Cisco uBR-MC88U line card in Cisco IOS software. |
Details for key command usage are provided below:
- To enable rate limiting on the given downstream port using the token bucket policing algorithm, issue the cable downstream rate-limit token-bucket command.
- To enable rate limiting on the given downstream port using the token bucket policing algorithm with traffic shaping, issue the cable downstream rate-limit token-bucket shaping command.
- To enable rate limiting on the given downstream port using the token bucket policing algorithm with a specific traffic shaping time granularity, issue the cable downstream rate-limit token-bucket shaping granularity 8 command. Acceptable values are 1, 2, 4, 8, or 16 msecs.
- To enable rate limiting on the given downstream port using the token bucket policing algorithm with a specific maximum traffic shaping buffering delay, issue the cable downstream rate-limit token-bucket shaping granularity 8 command. Acceptable values are 128, 256, 512, or 1028 msecs.
- To remove rate limiting on the given downstream port, issue the cable downstream rate-limit token-bucket command.
- To enable rate limiting on the given downstream port using a weighted packet discard policing algorithm and to assign a weight for the exponential moving average of loss rate value, issue the cable downstream rate-limit weighted-discard 3 command. Acceptable values are 1 to 4.
Setting the Downstream Helper Address
Specify an IP address of a Dynamic Host Configuration Protocol (DHCP) server where User Datagram Protocol (UDP) broadcast packets will be sent. You can specify a DHCP server for UDP broadcast packets from cable interfaces, and a DHCP server for UDP broadcast packets from hosts. To set a downstream helper address, use the following commands in cable interface configuration mode.
Verifying the Downstream Helper Address
To verify the downstream helper address setting, enter the show running-config command and look for cable helper-address in the cable interface configuration information:
Router# show running-config Building configuration... Current configuration: ! interface cable5/0 ip address 10.254.254.254 255.0.0.0 no ip directed-broadcast cable helper-address 192.168.1.1 no keepalive
Perform these steps if you are having difficulty with verification:
| Step 1 | Check the cables, upconverters, RF levels, and frequencies if the cable interfaces do not find a downstream signal. |
| Step 2 | Check the cables, RF levels, and upstream frequencies, and enter a no shut command if the cable interfaces find a downstream signal, but not an upstream signal. |
| Step 3 | Check the provisioning servers. |
| Step 4 | Check DHCP options and the IP address of the Time-of-Day (ToD)
server:
|
Setting the Downstream Interleave Depth
Set the interleave depth for the downstream port on the Cisco cable interface line card. A higher interleave depth provides more protection from bursts of noise on the HFC network; however, it increases downstream latency.
Note | The valid values are 8, 16, 32 (default), 64, and 128. |
To set the downstream interleave depth in milliseconds, use the following command in cable interface configuration mode:
Router(config-if)# cable downstream interleave-depth {8 | 16 | 32 | 64 | 128}
Verifying the Downstream Interleave Depth
To verify the downstream interleave depth setting, enter the show controllers cable command for the downstream port you have just configured:
Router# show controllers cable5/0 downstream Cable5/0 Downstream is up Frequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 Msps FEC ITU-T J.83 Annex B, R/S Interleave I=32, J=
Perform these steps if you are having difficulty with verification:
| Step 1 | Ensure that the cable connections are not loose or disconnected. |
| Step 2 | Ensure that the cable interface line card is firmly seated in its chassis slot. |
| Step 3 | Ensure that the captive installation screws are tight. |
| Step 4 | Verify that you have entered the correct slot and port numbers. |
| Step 5 | Verify that the downstream carrier is active, using the cable downstream if-output command. |
Setting the Downstream Modulation
To set the downstream modulation, define the speed in symbols per second at which data travels downstream to the subscriber’s CM. A symbol is the basic unit of modulation. Quadrature Phase Shift Key (QPSK) encodes 2 bits per symbol, Quadrature Amplitude Modulation (QAM) -16 encodes 4 bits per symbol, QAM-64 encodes 6 bits per symbol, and QAM-256 encodes 8 bits per symbol.
Note | Setting a downstream modulation rate of QAM-256 requires approximately a 6 dB higher signal-to-noise ratio (SNR) than QAM-64 at the subscriber’s cable interface. If your network is marginal or unreliable at QAM-256, use the QAM-64 format instead. Also, consider the significance of your data. |
To set the downstream modulation, use the following command in cable interface configuration mode. The standard DOCSIS modulation rate (and the Cisco default) is QAM-64.
Router(config-if)# cable downstream modulation 64qam
Verifying the Downstream Modulation
To verify the downstream modulation setting, enter the show controllers cable command for the downstream port you have just configured. See the following example:
Router# show controllers cable5/0 downstream Cable5/0 Downstream is up Frequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 Msps FEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4
Perform these steps if you are having difficulty with verification:
| Step 1 | Ensure that the cable connections are not loose or disconnected. |
| Step 2 | Ensure that the cable interface line card is firmly seated in its chassis slot. |
| Step 3 | Ensure that the captive installation screws are tight. |
| Step 4 | Verify that you have entered the correct slot and port numbers |
| Step 5 | Verify that the downstream carrier is active, using the cable downstream if-output command |
| Step 6 | Verify that you have selected the default if you are not certain about the modulation rate needed. |
Setting the Downstream MPEG Framing Format
The MPEG framing format must be compatible with DOCSIS specifications at:
http://www.cablelabs.com/cablemodem/ and your local cable plant operations.
Tip | Annex B is the DOCSIS MPEG framing format standard for North America. |
Note | Annex B framing format is automatically set when configuring Cisco cable interface line cards. The cable interface line card’s downstream ports and the connected CMs on the network must be set to the same MPEG framing format and must support DOCSIS operations as appropriate. |
The following command appears in the Cisco uBR7200 series router configuration file to designate Annex B operation. This command sets the downstream MPEG framing format.
Router(config-if)# cable downstream annex {B}
Verifying the Downstream MPEG Framing Format
To verify the downstream MPEG framing format setting, enter the show controllers cable command for the downstream port you have just configured. See the following example:
Router# show controllers cable5/0 downstream Cable5/0 Downstream is up Frequency=96000000, Channel Width 6 MHz, 64-QAM, Symbol Rate 5.056941 Msps FEC ITU-T J.83 Annex B, R/S Interleave I=32, J=4 Downstream channel ID: 1
Setting Downstream Traffic Shaping
Downstream traffic shaping enables you to use the token bucket policing algorithm with traffic shaping options or the weighted discard algorithm to buffer, shape, or discard packets that exceed a set bandwidth. Downstream traffic shaping is disabled by default.
To enable downstream traffic shaping for a downstream port on a Cisco cable interface line card, use one of the following commands in cable interface configuration mode.
| Command or Action | Purpose | |
|---|---|---|
| Step 1 |
cable
downstream
rate-limit
token-bucket
[shaping
[
granularity
msec
|
max-delay
msec]
Example: Router(config-if)# cable downstream rate-limit token-bucket Router(config-if)# cable downstream rate-limit token-bucket shaping Router(config-if)# cable downstream rate-limit token-bucket shaping granularity 8 Router(config-if)# cable downstream rate-limit token-bucket shaping max-delay 256 |
Enables traffic shaping on the downstream port using the token bucket policing algorithm. With this command, the Cisco uBR7200 series router automatically drops packets that are in violation of the allowable bandwidth. Enables traffic shaping on the downstream port using the token bucket policing algorithm with traffic shaping. Enables traffic shaping on the downstream port using the token bucket policing algorithm with specific traffic shaping time granularity. Acceptable values are 1, 2, 4, 8, or 16 milliseconds. Enables traffic shaping on the downstream port using the token bucket policing algorithm with specific maximum traffic shaping buffering delay. Acceptable values are 128, 256, 512, or 1028 milliseconds. |
| Step 2 |
cable
downstream
rate-limit
weighted-discard
exp-weight
Example: Router(config-if)# cable downstream rate-limit weighted-discard 3 |
Enables traffic shaping on the downstream port using the weighted discard algorithm and assigns a weight for the exponential moving average of the loss rate. Acceptable values are 1 to 4. |
| Step 3 | end
Example: Router(config-if)# end |
Exits back to privileged EXEC mode so that you can verify the steps. |
Verifying Downstream Traffic shaping
To determine if downstream traffic shaping is configured and activated, enter the show running-config command and look for the cable interface configuration information. If downstream traffic shaping is configured and enabled, a traffic shaping entry appears in the output. If downstream traffic shaping is disabled, no traffic shaping entry appears.
Router# show running-config Building configuration... Current configuration: ! interface cable5/0 ip address 10.254.254.254 255.0.0.0 no ip directed-broadcast cable helper-address 192.168.1.1 no keepalive cable downstream annex B cable downstream modulation 64qam
Perform these steps if you are having difficulty with verification:
| Step 1 | Ensure that the cable connections are not loose or disconnected. |
| Step 2 | Ensure that the cable interface line card is firmly seated in its chassis slot. |
| Step 3 | Ensure that the captive installation screws are tight. |
| Step 4 | Verify that you have entered the correct slot and port numbers. |
| Step 5 | Verify that you selected the default if you are not certain about the modulation rate needed. |
| Step 6 | Verify that the downstream carrier is active using the cable downstream if-output command. |
Activating Host-to-Host Communication (Proxy ARP)
Cable proxy ARP allows a Cisco CMTS router to issue cable ARP requests on behalf of CMs on the same cable network subnet.
Note | Because the downstream and upstreams are separate interfaces, modems cannot directly perform ARP with other modems on the cable plant. |
Note | The default values for the commands used in this configuration task are adequate in most cases to configure the Cisco CMTS routers. |
Activating Cable Proxy ARP Requests
This configuration is optional. To activate cable proxy ARP for host-to-host communications, use the following command in cable interface configuration mode.
|
Command |
Purpose |
|---|---|
Router(config-if)# cable proxy-arp |
Enables proxy ARP on the cable interface. This is the default. |
Verifying Cable Proxy ARP Requests
To verify if cable proxy ARP has been activated or deactivated, enter the more system:running-config command and look for the cable interface configuration information. If cable proxy ARP has been activated, it does not appear in the output. If cable proxy ARP has been deactivated, it appears in the output as no cable proxy-arp.
Router# more system:running-config Building configuration... Current configuration: ! interface cable5/0/0 ip address 1.1.1.1 255.255.255.0 no keepalive no cable proxy-arp cable downstream annex B cable downstream modulation 64qam cable downstream interleave-depth 32 cable downstream symbol-rate 5056941 cable upstream 0 frequency 15008000 no cable upstream 0 shutdown
Tip | If you are having difficulty with verification, make sure that you entered the correct port and cable interface line card slot number when you activated cable proxy ARP. |
Activating Packet Intercept Capabilities
This configuration is optional. To activate packet intercept functionality, use the following commands in cable interface configuration mode.
|
Command |
Purpose |
|---|---|
Router(config-if)# cable intercept xxxx.xxxx.xxxx
|
Specifies a MAC address on the cable network for which interception capabilities are to be activated. There is a limit of 10 MAC addresses. |
Router(config-if)# no cable intercept xxxx.xxxx.xxxx
|
Disables interception after it is enabled. |
Configuring Payload Header Suppression and Restoration
This configuration is optional. Payload Header Suppression (PHS) is a new feature in the DOCSIS1.1 MAC driver. The PHS feature is used to suppress repetitive or redundant portions in packet headers before transmission on the DOCSIS link. The upstream receive driver is now capable of restoring headers suppressed by CMs, and the downstream driver is capable of suppressing specific fields in the packet header before forwarding the frame to the CM.
|
Command |
Purpose |
|---|---|
show interface cable x/0/0 service-flow [sfid] phs |
Displays cable interface information. |
debug cable error |
Displays errors that occur in the cable MAC protocols. To disable debugging output, use the no form of the command. |
debug cable phs |
Displays the activities of the PHS and restoration driver. The no form of this command disables debugging output. |
Setting Optional Broadcast and Cable IP Multicast Echo
This configuration is optional. You can set additional IP parameters to enable downstream echoing of upstream data. This section contains two procedures to configure these optional IP parameters:
Note | The default values for the commands used in these configuration steps are adequate in most cases to configure the Cisco CMTS routers. |
- Setting IP Multicast Echo
- Verifying IP Multicast Echo
- Access Lists and the cable ip-multicast echo Command
- Setting IP Broadcast Echo
- Verifying IP Broadcast Echo
Setting IP Multicast Echo
The Cisco uBR10012 router echoes IP multicast packets by default. To activate IP multicast echo if it has been previously disabled, use the following command in cable interface configuration mode.
|
Command |
Purpose |
|---|---|
Router(config-if)# cable ip-multicast-echo |
Enables IP multicast echo. This is the default. |
To disable IP multicast echo, enter the no cable ip-multicast-echo command in cable interface configuration mode.
Verifying IP Multicast Echo
To determine whether IP multicast echo is activated or deactivated, enter the more system:running-config command, and look for the cable interface configuration information. If IP multicast echo is activated, there is no notation in the output, because this is the default setting. If IP multicast echo is deactivated, a notation appears in the output:
Router# more system:running-config Building configuration... Current configuration: ! interface cable5/0/0 ip address 1.1.1.1 255.255.255.0 no keepalive no cable ip-multicast-echo cable downstream annex B cable downstream modulation 64qam cable downstream interleave-depth 32 cable upstream 0 frequency 15008000 no cable upstream 0 shutdown
Tip | If you are having difficulty with verification, make sure that you entered the correct slot and port numbers when you entered cable interface configuration mode. |
Access Lists and the cable ip-multicast echo Command
The cable ip-multicast-echo command is enabled by default on the Cisco CMTS routers, so that multicast IP packets that arrive on the upstream at the Cisco CMTS are forwarded on the appropriate downstream ports so that they are delivered to the other CMs and CPE devices on that segment of the network. This allows the cable network to behave like a standard Ethernet network in terms of its handling of multicast IP traffic.
However, on the Cisco uBR10012 router, input access lists are not applied to the multicast traffic that is echoed on each downstream. To control the echoed multicast traffic, you therefore need to configure an output access list and apply it to each downstream interface.
Refer to the Cisco IOS CMTS Cable Command Reference Guide on Cisco.com for additional information on access lists and multicast echo:
http://www.cisco.com/en/US/docs/ios/cable/command/reference/cbl_book.html
Setting IP Broadcast Echo
By default, the Cisco uBR10012 router does not echo IP broadcast packets. To activate IP broadcast echo, use the following command in cable interface configuration mode.
|
Command |
Purpose |
|---|---|
Router(config-if)# cable ip-broadcast-echo |
Enables IP broadcast echo. |
To disable IP broadcast echo when it is enabled, enter the no cable ip-broadcast-echo command in cable interface configuration mode.
Verifying IP Broadcast Echo
To determine whether IP broadcast echo is activated or deactivated, enter the more system:running-config command and look for a notation in the cable interface configuration information:
Router# more system:running-config Building configuration... Current configuration: ! interface cable5/0/0 ip address 1.1.1.1 255.255.255.0 no keepalive cable ip-broadcast-echo cable downstream annex B cable downstream modulation 64qam cable downstream interleave-depth 32 cable upstream 0 frequency 15008000 no cable upstream 0 shutdown
Cable Interface Configuration Examples
This section provides the following configuration examples:
- Example: Subinterface Configuration
- Example: Cable Interface Bundling
- Example: Subinterface Definition on Bundle Master
- Example: Cable Interface Bundle Master Configuration
- Example: PE Router Configuration
- Example: Router Configuration
- Example: Configuring BGP Routing Sessions
- Example: Configuring PE-to-PE Routing Sessions
- Example: Configuring BGP PE-to-CE Routing Sessions
- Example: Configuring RIP PE-to-CE Routing Sessions
- Example: Configuring Static Route PE-to-CE Routing Sessions
Example: Subinterface Configuration
The following example shows how to define a subinterface on the cable5/0/0:
interface cable5/0/0 ! No IP address ! MAC level configuration only ! first subinterface interface cable5/0/0.1 description Management Subinterface ip address 10.255.1.1 255.255.255.0 cable helper-address 10.151.129.2 ! second subinterface interface cable5/0/0.2 ip address 10.279.4.2 255.255.255.0 cable helper-address 10.151.129.2 ! third subinterface interface cable5/0/0.3 ip address 10.254.5.2 255.255.255.0 cable helper-address 10.151.129.2
Example: Cable Interface Bundling
The following example shows how to bundle a group of physical interfaces. In this example, the interfaces int c5/0/0 and int c4/0 are bundled.
int c5/0/0 ip address 209.165.200.225 255.255.255.0 ip address 209.165.201.1 255.255.255.0 secondary cable helper-address 10.5.1.5 ! MAC level configuration cable bundle 1 master int c4/0/0 ! No IP address ! MAC layer configuration only cable bundle 1
Example: Subinterface Definition on Bundle Master
The following example shows how to define subinterfaces on a bundle master and define Layer 3 configurations for each subinterface. In this example, the interfaces int c5/0/0 and int c4/0/0 are bundled.
int c5/0/0 ! No IP address ! MAC level configuration only cable bundle 1 master int c4/0/0 ! No IP address ! MAC layer configuration cable bundle 1 ! first subinterface int c5/0/0.1 ip address 10.22.64.0 255.255.255.0 cable helper-address 10.4.1.2 ! second subinterface int c5/0/0.2 ip address 10.12.39.0 255.255.255.0 cable helper-address 10.4.1.2 ! third subinterface int c5/0/0.3 ip address 10.96.3.0 255.255.255.0 cable helper-address 10.4.1.2
Example: Cable Interface Bundle Master Configuration
The following example shows how to configure cable interface bundles:
Displaying the contents of the bundle Router(config-if)# cable bundle ? <1-255> Bundle number Router(config-if)# cable bundle 25 ? master Bundle master <cr> Router(config-if)# cable bundle 25 master ? <cr> Router(config-if)# cable bundle 25 master Router(config-if)# 07:28:17: %uBR10000-5-UPDOWN: Interface Cable5/0/0 Port U0, changed state to down 07:28:18: %uBR10000-5-UPDOWN: Interface Cable5/0/0 Port U0, changed state to up
Example: PE Router Configuration
This example (system information display) identifies the version of Cisco IOS software installed and displays PE configurations:
! Defines the hostname of the Cisco uBR10012 hostname region-1-ubr ! ! Describes where the system is getting the software image it is running. In ! this configuration example, the system is loading a Cisco uBR10012 image named ! AdamSpecial from slot 0. boot system flash slot0:uBR10000-p-mz.AdamSpecial ! ! Creates the enable secret password. enable secret xxxx enable password xxxx ! ! Sets QoS per modem for the cable plant. no cable qos permission create no cable qos permission update cable qos permission modems ! ! Allows the system to use a full range of IP addresses, including subnet zero, for ! interface addresses and routing updates. ip subnet-zero ! ! Enables Cisco Express Forwarding. ip cef ! ! Configures a Cisco IOS Dynamic Host Configuration Protocol (DHCP) server to insert the ! DHCP relay agent information option in forwarded BOOTREQUEST messages. ip dhcp relay information option ! ! Enters the virtual routing forwarding (VRF) configuration mode and maps a VRF table to ! the virtual private network (VPN) called MGMT-VPN. The VRF table contains the set of ! routes that points to or gives routes to the CNR device, which provisions the cable ! modem devices. Each VRF table defines a path through the MPLS cloud. ip vrf MGMT-VPN ! ! Creates the route distinguisher and creates the routing and forwarding table of the ! router itself. rd 100:1 ! ! Creates a list of import and/or export route target communities for the VPN. route-target export 100:2 route-target export 100:3 ! ! Maps a VRF table to the VPN called ISP1-VPN. ip vrf ISP1-VPN ! ! Creates the route distinguisher and creates the routing and forwarding table of the ! router itself. rd 100:2 ! ! Creates a list of import and/or export route target communities for the VPN. route-target import 100:1 ! ! Maps a VRF table to the VPN called ISP2-VPN. ip vrf ISP2-VPN ! ! Creates the route distinguisher and creates the routing and forwarding table of the ! router itself. rd 100:3 ! ! Creates a list of import and/or export route target communities for the VPN. route-target import 100:1 ! ! Maps a VRF table to the VPN called MSO-isp. Note: MSO-isp could be considered ISP-3; in ! this case, the MSO is competing with other ISPs for other ISP services. ip vrf MSO-isp ! ! Creates the route distinguisher and creates the routing and forwarding table of the ! router itself. rd 100:4 ! ! Creates a list of import and/or export route target communities for the VPN. route-target import 100:1 ! ! Builds a loopback interface to be used with MPLS and BGP; creating a loopback interface ! eliminates unnecessary updates (caused by physical interfaces going up and down) from ! flooding the network. interface Loopback0 ip address 10.0.0.0 255.255.255.0 no ip directed-broadcast ! ! Assigns an IP address to this Fast Ethernet interface. MPLS tag-switching must be ! enabled on this interface. interface FastEthernet0/0/0 description Connection to MSO core. ip address 10.0.0.0 255.255.255.0 no ip directed-broadcast full-duplex tag-switching ip ! ! Enters cable interface configuration mode and configures the physical aspects of the ! 5/0/0 cable interface. Please note that no IP addresses are assigned to this interface; ! they will be assigned instead to the logical subinterfaces. All other commands for ! this cable interface should be configured to meet the specific needs of your cable RF ! plant and cable network. interface Cable5/0/0 no ip address ip directed-broadcast no ip mroute-cache load-interval 30 no keepalive cable downstream annex B cable downstream modulation 64qam cable downstream interleave-depth 32 cable downstream frequency 855000000 cable upstream 0 frequency 30000000 cable upstream 0 power-level 0 no cable upstream 0 shutdown cable upstream 1 shutdown cable upstream 2 shutdown cable upstream 3 shutdown cable upstream 4 shutdown cable upstream 5 shutdown ! ! Configures the physical aspects of the 5/0/0.1 cable subinterface. If cable modems have ! not been assigned IP addresses, they will automatically come on-line using the settings ! for subinterface X.1. interface Cable5/0/0.1 description Cable Administration Network ! ! Associates this interface with the VRF and MPLS VPNs that connect to the MSO cable ! network registrar (CNR). The CNR provides cable modems with IP addresses and other ! initialization parameters. ip vrf forwarding MSO ! ! Defines a range of IP addresses and masks to be assigned to cable modems not yet associated with an ISP. ip address 10.0.0.0 255.255.255.0 ! ! Disables the translation of directed broadcasts to physical broadcasts. no ip directed-broadcast ! ! Defines the DHCP server for cable modems whether they are associated with an ISP or ! with the MSO acting as ISP. cable helper-address 10.4.1.2 cable-modem ! ! Defines the DHCP server for PCs that are not yet associated with an ISP. cable helper-address 10.4.1.2 host ! ! Disables cable proxy Address Resolution Protocol (ARP) and IP multicast echo on this ! cable interface. no cable proxy-arp no cable ip-multicast-echo ! ! Configures the physical aspects of the 5/0/0.2 cable subinterface. interface Cable5/0/0.2 description MSO as ISP Network ! ! Assigns this subinterface to the MPLS VPN used by the MSO to supply service to ! customers—in this case, MSO-isp. ip vrf forwarding MSO-isp ! ! Defines a range of IP addresses and masks to be assigned to cable modems associated ! with the MSO as ISP network. ip address 10.1.0.0 255.255.255.0 secondary ! ! Defines a range of IP addresses and masks to be assigned to host devices associated ! with the MSO as ISP network. ip address 10.1.0.0 255.255.255.0 ! ! Disables the translation of directed broadcasts to physical broadcasts. no ip directed-broadcast ! ! Defines the DHCP server for cable modems whether they are associated with an ISP or ! with the MSO acting as ISP. cable helper-address 10.4.1.2 cable-modem ! ! Defines the DHCP server for PC host devices. cable helper-address 10.4.1.2 host ! ! Disables cable proxy Address Resolution Protocol (ARP) and IP multicast echo on this ! cable interface. no cable proxy-arp no cable ip-multicast-echo ! ! Configures the physical aspects of the 5/0.3 cable subinterface interface Cable5/0/0.3 description ISP1's Network ! ! Makes this subinterface a member of the MPLS VPN. ip vrf forwarding isp1 ! ! Defines a range of IP addresses and masks to be assigned to cable modems associated ! with the MSO as ISP network. ip address 10.1.1.1 255.255.255.0 secondary ! ! Defines a range of IP addresses and masks to be assigned to host devices associated ! with the MSO as ISP network. ip address 10.0.1.1 255.255.255.0 ! ! Disables the translation of directed broadcasts to physical broadcasts. no ip directed-broadcast ! ! Disables cable proxy Address Resolution Protocol (ARP) and IP multicast echo on this ! cable interface. no cable proxy-arp no cable ip-multicast-echo ! ! Defines the DHCP server for cable modems whether they are associated with an ISP or ! with the MSO acting as ISP. cable helper-address 10.4.1.2 cable-modem ! ! Defines the DHCP server for PC host devices. cable helper-address 10.4.1.2 host ! ! Configures the physical aspects of the 5/0/0.4 cable subinterface interface Cable5/0/0.4 description ISP2's Network ! ! Makes this subinterface a member of the MPLS VPN. ip vrf forwarding isp2 ! ! Defines a range of IP addresses and masks to be assigned to cable modems associated ! with the MSO as ISP network. ip address 10.1.2.1 255.255.255.0 secondary ! ! Defines a range of IP addresses and masks to be assigned to host devices associated ! with the MSO as ISP network. ip address 10.0.1.1 255.255.255.0 ! ! Disables the translation of directed broadcasts to physical broadcasts. no ip directed-broadcast ! ! Disables cable proxy Address Resolution Protocol (ARP) and IP multicast echo on this ! cable interface. no cable proxy-arp no cable ip-multicast-echo ! ! cable dhcp-giaddr policy ! !! Defines the DHCP server for cable modems whether they are associated with an ISP or ! with the MSO acting as ISP. cable helper-address 10.4.1.2 cable-modem ! ! Defines the DHCP server for PC host devices. cable helper-address 10.4.1.2 host ! ! end
Example: Router Configuration
This example (system information display) identifies the version of Cisco IOS software installed and displays PE configurations:
Building configuration... Current configuration: ! version 12.0 service timestamps debug uptime service timestamps log uptime no service password-encryption ! hostname R7460-7206-02 ! enable password xxxx ! ip subnet-zero ip cef ip host brios 223.255.254.253 ! interface Loopback0 ip address 10.2.1.3 255.255.255.0 no ip directed-broadcast ! interface Loopback1 no ip address no ip directed-broadcast no ip mroute-cache ! interface FastEthernet0/0/0 ip address 1.7.108.2 255.255.255.0 no ip directed-broadcast no ip mroute-cache shutdown full-duplex no cdp enable ! router ospf 222 network 10.0.1.0 255.255.255.0 area 0 network 10.0.2.0 255.255.255.0 area 0 network 10.0.3.0 255.255.255.0 area 0 network 10.0.4.0 255.255.255.0 area 0 network 20.2.1.3 255.255.255.0 area 0 ! ip classless no ip http server ! ! map-list test-b no cdp run ! tftp-server slot0:master/120/ubr10k-p6-mz.122-2.XF ! line con 0 exec-timeout 0 0 password xxxx login transport input none line aux 0 line vty 0 4 password xxxx login ! no scheduler max-task-time end
Example: Configuring BGP Routing Sessions
To configure BGP routing sessions in a provider network, use the following commands in router configuration mode on the PE router:
| Step 1 | Configure the BGP routing process with the autonomous system
number:
Example: Router(config)# router bgp 42 |
| Step 2 | Specify a neighbor's IP address or BGP peer group, identifying it
to the local autonomous system:
Example: Router(config-router)# neighbor 200.28.28.40 Activate the advertisement of the IPv4address family. Router(config-router)# neighbor 200.28.28.40 activate |
Example: Configuring PE-to-PE Routing Sessions
To configure PE-to-PE routing sessions in a provider network, use the following commands in router configuration mode on the PE router:
| Step 1 | Define internal Border Gateway Protocol (iBGP) parameters for
VPNv4 network-layer reachability information (NLRI) exchange:
Example: Router(config-router)# address-family vpnv4 unicast |
| Step 2 | Define an IBGP session to exchange VPNv4 NLRIs:
Example: Router(config-router-af)# neighbor 200.28.28.45 remote-as 48 Router(config-router-af)# exit |
| Step 3 | Activate the advertisement of the IPv4address family:
Example: Router(config-router)# neighbor 200.28.28.45 activate |
Example: Configuring BGP PE-to-CE Routing Sessions
To configure BGP PE-to-CE routing sessions, use the following commands in router configuration mode on the PE router:
| Step 1 | Define external Border Gateway Protocol (eBGP) parameters for
PE-to-CE routing sessions:
Example: Router(config-router)# address-family ipv4 unicast vrf go_fast_internet_company |
| Step 2 | Define an eBGP session between PE and CE routers and activate the
advertisement of the IPv4 address family:
Example: Router(config-router-af)# neighbor 200.28.28.46 remote-as 49 Router(config-router-af)# neighbor 200.28.28.46 activate |
Example: Configuring RIP PE-to-CE Routing Sessions
To configure RIP PE-to-CE routing sessions, use the following commands in router configuration mode on the PE router:
Example: Router(config)# router rip Router(config-router)# address-family ipv4 unicast vrf go_fast_internet_company Router(config-router-af)# network 200.28.28.47 |
Example: Configuring Static Route PE-to-CE Routing Sessions
To configure static route PE-to-CE routing sessions, use the following commands in router configuration mode on the PE router:
| Step 1 | Define static route parameters for each PE-to-CE session and for
each BGP PE-to-CE routing session.
Example: Router(config)# ip route vrf go_fast_internet_company 200.28.28.46 255.255.255.0 200.28.28.50 Router(config-router)# address-family ipv4 unicast vrf go_fast_internet_company |
| Step 2 | Redistribute VRF static routes and directly connected networks
into the VRF BGP table.
Example: Router(config-router-af)# redistribute static Router(config-router-af)# redistribute static connected |
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