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Cable Modem Terminate System

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1 Cable Modem Terminate System
Setup 主講: Devil_huang

2 What is CMTS ? Cable Modem Terminate System (CMTS) The Router Gateway

3 1.The Router Route data between a cable modem network and a head-end internetwork 2.Gateway CMTS provides the encapsulation and de-capsulation of DOCSIS traffic. In upstream traffic ,it translates DOCSIS data to IP data then forwards to backbone network. In downstream traffic , it translates IP data to DOCSIS data and forwards the result to a cable modem. 2

4 Simplified Cable Headend Configuration for Two-way Data

5 CMTS function Performing MAC and PHY reception and transmission functions Packet classification Priority queuing Modification Filtering Routing Priority routing Proxy services Data encryption Encapsulating packets in the data link layer Extracts Ethernet packets Tunes each upstream channel Demodulates upstream data Modulates downstream data Adding forward error correction 4

6 Abbreviation CMTS: Cable Modem Terminate System CM: Cable Modem
DOCSIS: Data Over Cable Service Interface Specification DHCP: Dynamic Host Configuration Protocol CPE: Customer Premises Equipment ISP: Internet Service Provider TFTP: Trivial File Transfer Protocol TOD: Time Of Date ARP: Address Resolution Protocol AAI: Aggregate Access Interface MIC: Message Integrity Check CA: Certificate Authority SNMP: Simple Network Management Protocol BPI: Baseline Privacy Initialization ACL: Access Control List CLI: Command Line Interface QoS: Quality Of Service CMS: Call Management Server RKS: Record Keeping server MIB: Management Information Base 5

7 Architecture MSO Backbone Network CM Access Network Next-hop Router
DHCP/FTP/WEB Server ISP CM Access Network CPE CM 6

8 Packet-Cable Functionality chart

9 Sample Network

10 What should be specify ? Cable Access Interface
Fast Ethernet Interface Backbone Router DHCP / TFTP / TOD / Log server MIC Configuration Privacy Configuration RF Configuration CMTS Unit Interfaces 9

11 Logging In CMTS Privilege modes Logging In Need password to access
Non-privileged Mode:can access all reports and diagnostics cannot modify the system configuration Privileged Mode: can modify the system configuration Logging In Type enable puts the CLI in Privileged mode. Need password to access Type config terminate to get into the configuration context. And type username devil password letmein to create new user account. Type do show username to verify the account. 10

12 Configuring A Backbone Fast Ethernet Interface
Type configure t to get into configuration context , where you can start configuring Type interface fastethernet {0/0/0 | 0/0/1| 0/0/2 | 0/0/3} This command identifies specific fast Ethernet interface you are about to configure. Type ip address a.b.c.d e.f.g.h This command identifies a.b.c.d as the fast Ethernet ‘s IP address, e.f.c.d as its subnet mask. Type do show interface ip to verify the configuration Type no shutdown to enable the interface. Example: Terayon CMTS(config-if 0/0/0) # ip add 11

13 Configuring the Next-Hop Route
The next-hop route defines the backbone router the CMTS is connected to.In the factory , it always be combined to the server directly.So the route IP address will be replaced with the server’s IP address. Type ip route {network prefix} {netmask} {next-hop route IP address} Example: Terayon CMTS (config)# ip route In this example ,network prefix and netmask are fill with 0. This identifies all packet data should route to 12

14 AAI concept Aggregate Access Interface
Cable modem access interface provided by CMTS. Handles the routing of IP packets to the multiple physical cable interface ,thus keeping the HFC-plant configuration independent of the IP address domains. You can configure the baseline IP network to use a private or non-routable network IP address for CMs only. This avoids the use of public IP addresses for CMs 13

15 Aggregated Access Interface

16 Configuring the AAI Type interface access 0 to get into the access configuration context. Type ip address a.b.c.d e.f.g.h to identifies the CM access network IP Type ip address a.b.c.d e.f.g.h secondary to identifies the CPE access network IP Type cable helper-address {ip-address} [cable-modem | host] to identifies the DHCP server’s address. Example: Terayon CMTS(config-if-AAI-0)# cable helper 15

17 Configuring the AAI Configure the gateway interface address (giaddr) for the CM and CPE access networks on the global Aggregated Access using the command: cable dhcp-giaddr {policy | primary} If you select policy , the CM and CPE networks use a different giaddr . If you select primary , the CM and CPE networks use the same giaddr. Example: Terayon CMTS ( config-if-AAI-0) # cable dhcp- giaddr policy 16

18 MIC configuring Type interface cable CMTS unit number to specify the unit you want to configure. Type cable shared-secret word to specify the shared-secret authentication string. Use no prefix to disable MIC. Example: Terayon CMTS (config-if-1) # cable shared-secret DOCSIS Default string. annex A : Euro-DO annex B : DOCSIS One of the many features the CMTS has is its ability to verify the authentication of a DOCSIS® modem. This is accomplished through the authentication string the modem downloads in its configuration file.The authentication string is encrypted , then the modem transmits the string to the CMTS for verification. The process is called Message Integrity Check.

19 RF Configuration Downstream configuration
Type interface cable CMTS unit number to specify the unit you want to configure. Downstream configuration Type cable downstream frequency to specify the center frequency of the downstream channel. The valid ranges for the value are : <91MHz – 857MHz> for no.America and Japan <112MHz – 858MHz> for Europe. Type cable downstream power to specify the power level that CMTS output. Use the following command to set the downstream modulation type cable downstream modulation {64qam | 256qam}

20 RF Configuration Upstream configuration
Type cable upstream {0-3} {0|1} frequency to specify the upstream center frequency. The parameter {0-3} indicates the physical upstream port you are configuring The parameter {0|1} indicates the channel mode to which the center frequency will apply. 0 for TDMA 1 for S-CDMA The frequency value’s valid ranges are: <5MHz – 42MHz> for North-America <5MHz – 65MHz> for Europe <5MHz – 55MHz> for Japan

21 RF Configuration Verify the US / DS center frequencies
Terayon CMTS (config-if-1)# do show cable 1 upstream 0 0 Terayon CMTS (config-if-1)# do show cable 1 upstream 0 1 Terayon CMTS (config-if-1)# do show cable 1 downstream Enabling the interface Type no shutdown to enable CMTS unit interfaces.

22 RF Configuration Example:
Terayon CMTS (config-if-1)#cable upstream 0 0 freq Terayon CMTS (config-if-1)#cable downstream freq Terayon CMTS (config-if-1)# no shutdown This command enables the CMTS Unit MAC interface Terayon CMTS (config-if-1)# no cable upstream 0 shutdown Terayon CMTS (config-if-1)# no cable upstream 0 0 shutdown Terayon CMTS (config-if-1)# no cable downstream shutdown

23 DOCSIS 1.0 / 1.1 /2.0 Item upstream BPI DOCSIS1.0 TDMA disable

24 Viewing Status Viewing Cable Interface Status
Terayon CMTS(config-if-1) # do show interfaces cable Intf Type MTU Speed MACaddr. Oper Admin status (bps) status status Viewing Cable Modem Status do show cable modem MAC IP Cable Prim Chan MAC Timing RxPwr Unm Address Address I/F SID Mode State offset (db) CPE 00e0.6f23.72c /1/0/ tdma online(t)

25 BPI Baseline Privacy Initialization
Security is an issue of prime importance with the CMTS. By the term security we mean access and privilege levels ,authentication ,network privacy ,data filtering, and hostile-attack protection. download configuration file from server to determine enable BPI or disable. Use the cable privacy command to enter the configuration for privacy and BPI

26 Configuring cable privacy
Create a list of trusted / un-trusted cable modem Use the cable privacy hotlist command to create a list (Hotlist) of un-trusted cable modem Cable modem on the Hotlist are never authorized and are always denied service. Use the cable privacy trusted-list command to create a list (trusted-list) of trusted cable modem Cable modem on the trusted-list are always authorized for service and no authentication checking is performed. The same cable modem cannot be entered on both Hotlist and Trusted-list lists. Terayon CMTS(config)# [no] cable privacy hotlist H.H.H {manufacturer cert-ref-no} . Where H.H.H specifies a MAC address and cert-ref-no is the reference number assigned to this Manufacturer’s Certificate.

27 Configuring cable privacy
Certificate Use the cable privacy certificate {root | manufacturer} cert-ref-no command to enable or disable CA certificates. The CMTS maintains a list of known certificates classified in three categories,Root and Manufacturer Certificates. Root Certificates added are marked as ‘root’ and by default marked trusted.for operation purposes , the system requires only one active Root Certificate. Manufacturer Certificates added are marked as ‘trusted’ by default.The command cable privacy hotlist allows marking a Certificate as ‘un-trusted’.

28 Configuring cable privacy
Certificate (continue) Manufacturer Certificates can be added/ modified.When the certificate be added , a unique reference number is automatically assigned to it and displayed on the command line.This reference number may be used later to display information about this certificate or to delete this certificate from the database. Example: Terayon CMTS(config)# cable privacy certificate root cert-ref-no 2 for American or Japan. Terayon CMTS(config)# cable privacy certificate root cert-ref-no 3 for Europe.

29 Configuring cable privacy
Self-signed Certificates The CMTS policy to accept self-signed manufacturer certificates from cable modems at authorization time. Use the accept-self-signed-certificate command to accept self-signed manufacturer certificates. It is always set on a per-cable-line-card basis. Enabling the Validity Period Check The CMTS verifies the validity period of cable modem certificates( at KEK exchange times), using its time-of-day clock as the time reference for the verification. Use the validity-period-check command to force verification of the modem certificate validity period.

30 Configuring cable privacy
Key Encryption Key/Traffic Encryption Key lifetime When BPI is enabled (in the cable modem configuration file),the CMTS and the cable modem use authorization and encryption / decryption for packet across the HFC interface.The BPI is configured with KEKs and TEKs. A KEK is assigned to a cable modem based on the cable modem’s service identifier(SID) and permits the connection when baseline privacy is activated. The TEK is assigned to a cable modem when its KEK has been established.It is used to encrypt data traffic between cable modems. KEK and TEK can be set to expire based on a lifetime value.New keys are requested before the current ones expire. Use the no form of the command to return to the default condition .

31 Configuring cable privacy
Setting the Registration Timeout Use the registration-timeout command to set the value of the DOCSIS registration timeout timer(T9 timeout) on a particular interface. The registration timeout is the time allowed between the CMTS sending a RNG-RSP (ring-response success) to a CM and receiving a REG-REQ(registration request) from that same CM. Configuring the Shared Secret String(MIC) Use the default cable shared-secret command to set the default shared secret string.

32 Configuring cable privacy
Setting UP Basic Access Control Lists This allows defining a list of host names or IP address to be permitted or denied access. Display and diagnose security parameters Displaying Privacy certificates show cable privacy certificate {root | manufacturer cert-ref-no} show cable privacy certificate modem H.H.H Displaying Interface Privacy Information show cable privacy interface

33 The modem configuration file
The modem configuration file is stored as a binary file.It can be edited using a special tool. Use a designated TFTP server to make your modem configuration file available for remote configuration. Example setting for DOCSIS2.0 modem: Privacy Enable(29) =0 Service Flow Reference(24.1) = 1 Quality of Service Parameter Set Type (24.6) = 7 Network Access Control Object(3) = 1 Maximum Number of CPEs (18) = 2 Upstream Service Flow encoding(24) Downstream Service Flow Encoding(25) Service Flow Reference (25.1) = 5 Quality of Service Parameter Set Type (25.6) = 7

34 The DHCP Relay Agent Each modem and host can get an IP address and IP information from a DHCP server connected to the CMTS.The CMTS servers as a relay agent between the DHCP server and the modems and implements the DHCP/BootP relay agent.

35 The DHCP Relay Agent

36 Address Resolution Protocol Function
The CMTS supports the ARP protocol, a protocol used to obtain a device physical (layer 2 MAC) address based on its logical (layer 3 IP) address.In short,ARP binds high level IP address to low level physical address.However , the CMTS handles ARP differently for the backbone , management, and cable interface. Entries both for CM and CPE. Each ARP table entry associates a single IP address with a singe host. Supporting Dynamic and Static ARP entries Extended ARP type ARP learning

37 ARP Function

38 ARP configuration Aging timeout
This allows you to set the threshold when you want dynamic ARPs to age out Terayon CMTS(config)# arp timeout < > Where < > is the timeout value in seconds. The value indicates that there is no timeout and the dynamic ARPs do not age out.

39 ARP configuration Proxy ARP
The Proxy ARP feature works on only the cable network side of the CMTS. This reduces network ARP traffic overhead ,thus improving network performance, and at the same time increases network security When a cable network host send an ARP request to the CMTS, instead of broadcasting that request to the cable modem network ,the CMTS responds to the ARP request and then relays the request to the appropriate host on the cable network.In the host ARP tables, the destination MAC address is always the CMTS MAC address The default condition of the Proxy ARP feature is enabled

40 ARP configuration ARP Learning feature
This enables you to stop clients that obtain IP addresses via dynamic ARP from passing traffic,thus forcing the client (CPE) to obtain an IP address via a DHCP transaction. If you disable ARP Learning on the access side, the CMTS ARP table entries only from Static ARP and DHCP ARP assignments.Dynamic ARPs and host MAC addresses for Static-host ARPs are not learned. The ability to enable and disable ARP Learning gives you strict control over ARP table entries,resulting in a higher degree of protection against IP address spoofing.(unauthorized devices attempting to steal or mimic a valid IP address). The default condition for ARP learning on the access side is enabled

41 ARP configuration Clear ARPs on Modem Reset
You may configure the CMTS to clear (remove) CPE ARPs whenever a cable modem resets. This may be useful when the IP limit for a modem is 2 or greater If the Lease Query (source IP address verification) feature is disabled ,then enabling the ARP clear-on-reset feature has no effect. Terayon CMTS(config)# arp clear-on-reset

42 Server Configuration Operating System (OS) Software
Win2000 professional Service Path 4 Internet Information Services. Win2000 Server Win2000 Advance Server Software Cisco Network Register 3.0 (DHCP Server) tardis2000nt (TOD Server) TFTP 2000 (TFTP Server)

43 Server Configuration Internet Information Services Setup HTTP support
Web service FTP support Setup 1. Start  2. Setting  3.Control Panel  4. Add/Remove Programs  5.Add/Remove Windows Component  6.Windows Component Wizard  7.Select IIS  8. Press Next  Finish FTP service Scripts support POP3 / SMTP support

44 4 3 2 IIS setup 1

45 6 5 7 8 IIS setup

46 IIS setup After finished software install.The following folders will be created in disk C. Inetpub FTProot WWWroot The file which named default.htm in WWWroot will used as the web server’s default web. The files in FTProot will displayed in FTP server’s folder.

47 Default.htm IIS setup

48 FTP Configuration Enabling FTP service
1.Start  2. Setting  3.Control Panel  4. Administrative tools  5.Service  6. Select FTP Publishing Service  7.Start the service  8. Set the start-up type automatic  Finish Copy files you want to shell to FTProot.

49 4 5 3 2 Enabling FTP service 1

50 FTP Publishing Service
Enabling FTP service

51 DHCP Configuration Software setup Login in the system Add scope
Policy configuration Time offset Router DHCP lease time Time Server Packet file name Log server Use interface configuration

52 TOD setup Log into your Windows NT system as a user with administrative privileges. Tardis 2000 NT must be installed and configured by someone with administrative privileges. Run the tardis2000NT.exe program and Tardis 2000 will automatically be installed. Choose start service / stop service as show in the following figure

53 Run Tardis 2000 NT

54 TFTP setup If you use TFTPD32.exe , Start the program at the same path of the CM configuration file If you use TFTP server pro 2000 ,configured the input path as the CM configuration file’s location

55 Troubleshooting Understand show command Responses
show cable modem show interface cable show cable privacy show arp show run Understand CM online procedure Understand CM online message Troubleshooting Cable Modem State

56 Troubleshooting Cisco CM State Offline State Ranging Process DHCP
init(r1),init(r2),init(rc)state DHCP init(d) , init ( i ) state TOD exchange: init(t) state Option file transfer started : init (o) state Online Online , Online(d) ,Online(pt) state Reject reject(pk) , reject(pt) , reject(m) ,reject(c) state

57 Troubleshooting Terayon CM State Offline Ranging Process Online
Offline , Offline(lr) , offline (ad) state Ranging Process init(r ) ,init(rc) ,init(ds) ,init(os) ,init(ip) state Online Online(pd),Online(tek) ,Online(kek) ,Online(t)

58 Troubleshooting Offline state most common reasons
Weak carrier signal ( too much noise ). Incorrect Downstream Center Frequency Incorrect Frequency Specified in the DOCSIS file Absence of downstream digital QAM modulated signal Incorrect frequency specified in cable modem change-frequency on the CMTS router Offline (lr) & Offline (ad) Offline (lr) :The line-card on which the modem came up on last time was deleted. Offline (ad): The modem is denied access. Check the configuration file of the modem.

59 Troubleshooting Ranging process Cisco Terayon
At this stage , the CM begins a ranging process to calculate the necessary transmit power level to reach the CMTS at its desired input power level Cisco init(r1) : Cable modem sent initial ranging init(r2) : Cable modem is ranging init(rc) : Cable modem ranging complete Terayon init(r ) : The modem is in ranging modem

60 Troubleshooting DHCP state DHCP request received Cisco : init (d)
After successful ranging ,it needs to acquire network configuration via DHCP. The CM sends a DHCP request and the CMTS relays those DHCP packets in both direction. DHCP request received Cisco : init (d) Terayon init (rc) : the modem is unable to get a DHCP address. init (ds) : DHCP discover is sent and waiting for offer.

61 Troubleshooting DHCP request received state most common reason.
Missing cable helpler-address <IP-address> command on the CMTS or incorrect < IP-address> DHCP server down IP connectivity issue from the CMTS to the DHCP server Wrong default gateway configured at the DHCP server Low transmit power at the CM or low upstream SNR,see RF Specifications DHCP server overload DHCP server is out of IP addresses Reserved IP address for modem is inside wrong scope.

62 Troubleshooting DHCP reply received ; IP address assigned
Cisco: init( i ) Terayon : init( os ) Most common reason Incorrect or invalid DOCSIS file specified in the DHCP server TFTP server issues , for example incorrect ip address,TFTP server unreachable Problems getting TOD or Timing Offset Incorrect Router setting in the DHCP configuration

63 Troubleshooting TOD exchange – init( t ) state
You can only see this at Cisco’s CMTS Almost always point to a DHCP mis-configuration Wrong TOD server address TOD server is unavailable.

64 Troubleshooting Option file transfer started state Most common reason
Cisco : init ( o ) Terayon : init (ip) Most common reason Incorrect,corrupt (for example: ASCII instead of binary), or missing DOCSIS configuration file. Unable to reach the TFTP server ,either is unavailable , too busy or no IP connectivity Invalid or missing Configuration Parameter in DOCSIS file Wrong file permissions on the TFTP server

65 Troubleshooting Online state Cisco Terayon
online : Cable modem registered , enabled for data online(d) : Cable modem registered ,but network access for the cable modem is disabled online(pk): Cable modem registered , BPI enabled and KEK assigned online(pt) : Cable modem registered,BPI enabled and TEK assigned Terayon online(pd) online(tek) online(kek) online(t)

66 Troubleshooting Reject state Most common reason Cisco
Reject(pk) and Reject(pt) state Reject(m) Most common reason Some problem with the BPI configuration Some problem with the MIC

67 Troubleshooting Full of log Example: application program log
Clear log at the server CM record log Clear log at CMTS Example: Terayon CMTS # clear cable modem offline delete

68 Thank you ! Devil

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