Cisco cBR 8 Configuration Manual page 44
Cbr series converged broadband routers
Hide thumbs
Also See for cBR 8:
- Installation instructions manual (27 pages) ,
- Configuration and troubleshooting manual (254 pages) ,
- Hardware installation manual (270 pages)
Table of Contents
Advertisement
Restrictions for DOCSIS 1.1 Operations
Ensure that the system clocks on the CMTS and on the time-of-day (ToD) servers are synchronized. If
Note
this does not occur, the clocks on the CMs will not match the clocks on the CMTS, which could interfere
with BPI+ operations. In particular, this could prevent the proper verification of the digital certificates on
the CM.
BPI+-Encrypted Multicast Not Supported with Bundled Subinterfaces on the Cisco cBR-8 Router
The current Cisco IOS-XE releases do not support using BPI+ encrypted multicast on bundled cable
subinterfaces on the Cisco cBR-8 router. Encrypted multicast is supported on bundled cable interfaces or on
non-bundled cable subinterfaces, but not when a subinterface is bundled on the Cisco cBR-8 router.
BPI+ Not Supported with High Availability Configurations
The current Cisco IOS-XE releases do not support using BPI+ encrypted multicast on a cable interface when
the interface has also been configured for N+1 (1:n) High Availability or Remote Processor Redundancy Plus
(RPR+) High Availability redundancy.
In addition, BPI+ is not automatically supported after a switchover from the Working cable interface to the
Protect cable interface, because the cable interface configurations that are required for BPI+ encryption are
not automatically synchronized between the two interfaces. A workaround for this is to manually configure
the Protect cable interfaces with the required configurations.
DOCSIS Root Certificates
The Cisco CMTS supports only one DOCSIS Root CA certificate.
Maximum Burst Size
Previously, the maximum concatenated burst size parameter could be set to zero to specify an unlimited value.
In a DOCSIS 1.1 environment, this parameter should be set to a nonzero value, with a maximum value of
1522 bytes for DOCSIS 1.0 cable modems.
If a cable modem attempts to register with a maximum concatenation burst size of zero, the DOCSIS 1.1
CMTS refuses to allow the cable modem to come online. This avoids the possibility that a DOCSIS 1.0 cable
modem could interfere with voice traffic on the upstream by sending extremely large data packets. Since
DOCSIS 1.0 does not support fragmentation, transmitting such data packets could result in unwanted jitter
in the voice traffic.
In addition, DOCSIS 1.1 requires that the maximum transmit burst size be set to either 1522 bytes or the
maximum concatenated burst size, whichever is larger. Do not set the maximum concatenation burst size to
values larger than 1522 bytes for DOCSIS 1.0 cable modems.
Note
This change requires you to change any DOCSIS configuration files that specify a zero value for the
maximum concatenation burst size. This limitation does not exist for DOCSIS 1.1 cable modems unless
fragmentation has been disabled.
Performance
DOCSIS 1.0 cable modems lack the ability to explicitly request and provide scheduling parameters for advanced
DOCSIS 1.1 scheduling mechanisms, such as unsolicited grants and real-time polling. DOCSIS 1.1 cable
Cisco cBR Series Converged Broadband Routers Quality of Services Configuration Guide for Cisco IOS XE
Fuji 16.7.x
34
DOCSIS 1.1 for the Cisco CMTS Routers
Hide quick links:
Advertisement
Table of Contents
