Subject: DOCSIS and DVB MIB Comparision

From: Rich Woundy <[email-masked]>
Date: Fri, 11 Feb 2000 19:20:49 -0500

Folks,

Andrew Valentine (Hughes Network Systems) and I have been working on the
comparison between the DOCSIS Cable Device MIB and the DVB NIU MIB. In
addition, we've thought a little bit about potentially merging the two MIBs
for future products such as dual DOCSIS/DVB set-top boxes.

Separately, Andrew is planning to publish the DVB NIU MIB as an Internet
draft. This MIB is the subject of this comparison report, and is similar to
the "Euromodem MIB" that Andrew posted to the ipcdn mailing list on 10/6/99.

I suspect that folks reading this report will generate comments back to
this mailing list, as well as in Adelaide.

-- Rich

DOCSIS and DVB MIB Comparision for Potential Merging 

First of all, why should we attempt to merge the DOCSIS Cable Device and
DVB NIU MIBs?

There are two primary reasons for merging at least part of the DOCSIS Cable
Device MIB with the DVB/Euromodem NIU MIB. First, the industry expects the
deployment of OpenCable and other advanced digital set-top boxes, which
contain both DOCSIS and DVB interfaces, likely under the control of a
single CPU with a single SNMP agent. Successful deployment of these devices
requires the following MIB objects that are not addressed by independent MIBs:
- an object that allows the MSO to reset the entire box, in addition to
objects to reset the DOCSIS and DVB components individually,
- objects representing "upstream traffic direction", that determine whether
upstream packets are forwarded to the DOCSIS or DVB component,
- objects managing "network management access" that consistently control
access to each modem's consolidated SNMP agent, and
- objects representing a consolidated "event log" for both DOCSIS and DVB
events that preserve sequences of events (to help isolate cable plant
issues from DOCSIS CMTS/DVB INA issues).

Second, the industry would benefit from consistency in cable modem
management. The CM vendors could reuse some SNMP agent software between
DOCSIS and DVB modems (and simplify software for an integrated DOCSIS/DVB
modem). The network management software vendors could write the same or
similar management applications, particularly managing the common MIB
objects for DOCSIS and DVB.

DVB NIU (Revision 9912010000Z) and DOCSIS Cable Modem (RFC2669) MIB Comparison

Only the objects in the DOCSIS MIB which are applicable to the modem have
been compared. The objects are compared in the order they appear in the MIBs.

KEY

(DOC) DOCSIS only object
(DVB) DVB only object
(DIF) Common object but different definition
(SIM) Similar object with similar definition

OBJECTS

(DVB) dvbNiuModemtype: Type of modem
(DOC) docsDevRole: Role of DOCSIS device

(DVB) dvbNiuMibVersion: Version of Niu MIB

(SIM) dvbNiuDateAndTime / docsDevDateTime

(DIF) dvbNiuResetNow / docsDevResetNow: Control reset of device
DVB object uses an Enumerated, DOCSIS MIB uses a TruthValue.

(DVB) dvbNiuResetCounts: Count of resets since power on

(DIF) dvbNiuSerialNum / docsDevSerialNumber
DVB object includes manufacturer, model, revision. DOCSIS puts similar
attributes into the System sysObjectID object: vendor ID, hardware
platform, hardware revision, software/PROM revision (major, minor, patch
numbers). The sysDescr object conveys the same information in
human-readable form. See DOCSIS SP-OSSI-RFI-I03-990113.

(DOC) docsDevSTPControl: Bridging spanning tree control

(DVB) dvbStaticIpTable (entire table): Static IP configuration of interfaces

(DIF) dvbNiuNmAccessTable / docsDevNmAccessTable (entire table): NM access
table
DVB object states that an empty table only allows management access via the
HFC interface.

(DIF) dvbNiuNmAccessStatus / docsDevNmAccessStatus: RowStatus
DVB object states that "Rows can be modified/deleted ONLY if the SNMP set
request source IP address will not be denied access after the set request
is actioned."

(DVB) dvbNiuConfigSet: Controls the storage of configuration information

(DVB) dvbNiuEuroLoader:  Controls EuroLoader

(DVB) dvbNiuImplSet:  Identifies which optional groups have been implemented

(DVB) dvbNiuSwVerTable (entire table): Table to manage multiple CM software
images

(SIM) dvbNiuSwServer / docsDevSwServer: TFTP server for software upgrades

(DIF) dvbNiuSwFilename / docsDevSwFilename: Filename of image to download
DOCSIS object has concept of DHCP-supplied filename.

(DVB) dvbNiuSwDownloadSlot: Select memory slot to download image into

(DIF) dvbNiuAdminStatus / docsDevSwAdminStatus + docsDevSwOperStatus
The DVB object combines the two DOCSIS objects.  The DOCSIS and DVB
enumerations are different, and are technology-specific.

(DOC) docsDevSwCurrentVers: Current operational software version

(DVB) dvbNiuDhcpTable (entire table): DHCP control table

(DVB) dvbNiuOperStatus: Operation status of box
(DOC) docsDevServerBootState: Boot state of box

(DOC) docsDevServerDhcp: IP address of DHCP server that assigned IP address

(DOC) docsDevServerTime: IP address of time server

(DOC) docsDevServerTftp: TFTP server for provisioning params

(DOC) docsDevServerConfigFile: Config file to be read from TFTP server

(DIF) dvbNiuEventPolicy / docsDevEvControl: Controls event logging
The DVB object has more enumerations for managing the log size.  DOCSIS
provides an enumeration to reset event priorities to their factory defaults.

(DOC) docsDevEvSyslog: IP address of Syslog server

(SIM) dvbNiuEvThrottleAdminStatus / docsDevEvThrottleAdminStatus

(SIM) dvbNiuEvThrottleInhibited / docsDevEvThrottleInhibited

(SIM) dvbNiuEvThrottleThreshold / docsDevEvThrottleThreshold

(SIM) dvbNiuEvThrottleInterval / docsDevEvThrottleInterval

(DIF) dvbNiuEventControlTable / docsDevEvControlTable: Event control table
Priority values (dvbNiuEventControlPriority/docsDevEvPriority) are the
same. Reporting action for DVB (dvbNiuEventControlAction) does not include
SYSLOG, but reporting action for DOCSIS (docsDevEvReporting) does include
SYSLOG.

(DVB) dvbNiuEventTableMaxSize: Max number of entries event log can hold

(DIF) dvbNiuEventTable / docsDevEvTable: Event log
For the DVB table each event creates a new row, whereas the DOCSIS table
allows a single row to represent multiple events of the same nature. The
DVB table also allows individual event entries to be deleted.

(DIF) dvbNiuDateAndTime / docsDevEvFirstTime + docsDevEvLastTime +
docsDevEvCounts
Because the DVB event table does not support multiple events per row only
one DateAndTime object is required.

(SIM) dvbNiuEventType / docsDevEvLevel

(SIM) dvbEventDescription / docsDevEvText

(DIF) dvbNiuEventCode / docsDevEvId: Code to uniquely identify the type of
event
The DVB object is a SnmpAdminString with a recommended structure, whereas
the DOCSIS object is an Unsigned32.

(DVB) dvbNiuEventStatus: RowStatus

(DIF) dvdNiuEthFilter + dvbNiuIpFilter / docsDevFilter: Ethernet/LLC and IP
filtering
Ethernet and IP filtering are optional to implement in DVB

(DOC) docsDevFilterLLCUnmatchedAction: Unmatched filter action
The DVB behavior is to discard packets if filtering is enabled but a match
is not found.

(DVB) dvbNiuEthernetFilterEnable: Enables/disables filters, and provides
debug feature

(DIF) dvbNiuEthernetFilterTable / docsDevFilterLLCTable

(SIM) dvbNiuEthernetFilterIndex / docsDevFilterLLCIndex

(SIM) dvbNiuEthernetFilterStatus / docsDevFilterLLCStatus

(SIM) docsDevFilterLLCIfIndex / dvbNiuEthernetFilterIfIndex

(DIF) dvbNiuEthernetFilterEtherType / docsDevFilterLLCProtocolType: Format
of protocol field
The DVB object enumeration distinguishes Ethernet2 and 802.2 SNAP frames,
whereas the DOCSIS object enumeration does not.

(SIM) dvbNiuEthernetFilterProtocol / docsDevFilterLLCProtocol

(DVB) dvbNiuEthernetFilterAction: Action to be performed if filter match.

(SIM) dvbNiuEthernetFilterMatches / docsDevFilterLLCMatches

(DOC) docsDevFilterIpDefault: Unmatched filter action
The DVB behavior is to discard packets if filtering is enabled but a match
is not found.

(DVB) dvbNiuIpFilterEnable: Enables/disables filters and provides debug
feature.

(DIF) dvbNiuIpFilterTable / docsDevFilterIpTable
Difference in naming convention and description.  With DVB packets are
always discarded if there is no matching filter.  DVB has no concept of a
policy table.

(SIM) dvbNiuIpFilterIndex / docsDevFilterIpIndex

(SIM) dvbNiuIpFilterStatus / docsDevFilterIpStatus

(DVB) dvbNiuIpFilterAssignedby:  How the entry was made in the table
The DVB MIB combines the DHCP anti-spoofing filters and general filters in
a single table.

(DIF) dvbNiuIpFilterAction / docsDevFilterIpControl:  What action to take
on a hit
The DVB object has extra different enumerations for TOS, NAT, NAPT as there
is no policy table.

(SIM) dvbNiuIpFilterIfIndex / docsDevFilterIpIfIndex

(SIM) dvbNiuIpFilterDirection / docsDevFilterIpDirection

(DOC) docsDevFilterIpBroadcast:  Filter applicable to Broadcast/Multicast
A single IP filter row can capture all IP broadcast/multicasts with this
object, including IP subnet broadcasts (e.g. 10.1.1.255), IP all-subnet
broadcasts (255.255.255.255), and IP multicasts (e.g. 224.0.1.1).

(SIM) dvbNiuIpFilterSrcAddr / docsDevFilterIpSaddr

(SIM) dvbNiuIpFilterSrcMask / docsDevFilterIpSmask

(SIM) dvbNiuIpFilterDstAddr / docsDevFilterIpDaddr

(SIM) dvbNiuIpFilterDstMask / docsDevFilterIpDmask

(SIM) dvbNiuIpFilterProtocol / docsDevFilterIpProtocol

(SIM) dvbNiuIpFilterSrcPortLow / docsDevFilterIpSourcePortLow

(SIM) dvbNiuIpFilterSrcPortHigh / docsDevFilterIpSourcePortHigh

(SIM) dvbNiuIpFilterDstPortLow / docsDevFilterIpDestPortLow

(SIM) dvbNiuIpFilterDstPortHigh / docsDevFilterIpDestPortHigh

(SIM) dvbNiuIpFilterMatches / docsDevFilterIpMatches

(SIM) dvbNiuIpFilterTos / docsDevFilterIpTos

(SIM) docsDevFilterIpTosMask / dvbNiuIpFilterTosMask

(SIM) dvbNiuIpFilterContinue / docsDevFilterIpContinue

(DIF) dvbNiuIpFilterActionPtr / docsDevFilterIpPolicyId: Points to an entry
in a table
The DVB object points into a table specific to each type of action defined
in dvbNiuIpFilterAction.  The DOCSIS object points into the policy table.

(DOC) docsDevFilterPolicyTable (entire table)
(DOC) docsDevFilterPolicyIndex
(DOC) docsDevFilterPolicyId
(DOC) docsDevFilterPolicyStatus
(DOC) docsDevFilterPolicyPtr

(SIM) dvbNiuIpTOSMapTable / docsDevFilterTosTable: TOS manipulation table
The DVB TOS Mapping table includes a policy ID.

(SIM) docsDevFilterTosIndex / dvbNiuIpTosMapIndex

(DVB) dvbNiuIpTosMapPolicyId

(SIM) docsDevFilterTosStatus / dvbNiuIpTosMapStatus

(SIM) docsDevFilterTosAndMask / dvbNiuIpTosMapAndMask

(SIM) docsDevFilterTosOrMask / dvbNiuIpTosMapOrMask

(DOC) docsDevCpeEnroll: controls population of docsDevFilterCpeTable

(DOC) docsDevCpeIpMax: Control number of CPEs allowed to connect behind device

(DOC) docsDevCpeTable (entire table):  CPE IP address based access control

(DVB) dvbNiuNatTable (entire table):  Network Address Translation (NAT) table

(DVB) dvbNiuNaptAddr: IP address used for NAPT (Network Address and Port
Translation)

(DVB) dvbNiuNaptTable (entire table): Network Address and Port Translation
(NAPT) table

Conclusion

To consolidate the MIBs into a single cable device MIB would result in a
MIB containing three logical components: the common component, the DOCSIS
component, and the DVB component. Note that most, if not all, of the
objects have been defined in the current DOCSIS Cable Device and/or DVB NIU
MIBs.

The common component of the merged MIB would contain the following object
groups:
- the Basic Modem Control group, with objects for modem type/role, date and
time, modem reset, modem reset count, serial number, MIB version, and
"implementation set",
- the Network Management Access Control group (to be replaced with SNMPv3
kickstart),
- the Event Logging group,
- the Ethernet/LLC Filtering group (with objects for upstream traffic
direction),
- the IP Filtering group (with objects for upstream traffic direction),
- the IP ToS Mapping group, and
- the CPE Management group (this may be part of the IP Filtering group).

The DOCSIS component of the merged MIB would contain the following object
groups:
- the DOCSIS Modem Control group, with objects for managing DOCSIS reset,
administrative status, operational status, spanning tree control, DHCP/Time
of Day/TFTP controls, and SYSLOG control, and
- the DOCSIS Software Management group (single image).

The DVB component of the merged MIB would contain the following object groups:
- the DVB Modem Control group, with objects for managing DVB reset,
administrative status, operational status, and Euroloader control, 
- the DVB Software Management group (multiple images),
- the Static Route Table group,
- the DHCP Relay group,
- the Network Address Translation group, and
- the Network Address and Port Translation group.