Hi,
I have been asked to do a MIB Doctors review of
draft-ietf-bess-l2l3-vpn-mcast-mib-02.txt.
My knowledge of L2L3VPN Multicast is limited to the reading
of this document and browsing through the documents referred
to in the draft and bess-wg mailing list archives.( read "shallow").
So some of the doubts and questions may sound trivial or
strange. Please bear with me and help me help you make
this into a better document :-)
The comments are attached.
Glenn
Comments on draft-ietf-bess-l2l3-vpn-mcast-mib-02.txt.
-----------------------------------------------------
This is a preliminary review. Once the following points are
taken care of, we can get down to a detailed in-depth review.
1. Abstract:
1.1 A sentence on how the managed objects will be used by
applications for operations, monitoring and management
would be good.
2. Introduction
2.1 Please give the full expansion of the abbreviations
appearing for the first time. (PE, VPLS,..)
2.2 The terminology section is a bit terse. Explaining the
terms that are used, nicely with reference to the protocol
documents will improve readability.
e.g.
- PMSI, I-PMSI, S-PMSI, provider tunnels
2.3 Is there a difference between
"multicast in Layer 2 and Layer 3 VPNs , defined by
RFC 7117 and RFC 6513/6514"
used in the DESCRIPTION in the MODULE-IDENTITY
and
"multicast in BGP/MPLS L2 or IP VPN"
used in the DESCRIPTION of L2L3VpnMcastProviderTunnelType ?
If these are the same, it will be helpful to stick to the
same expression. If these are not the same, the dictinction
should be clarified.
3. Summary of MIB Module.
An overview of the L2L3-VPN-MCAST-MIB will be good- the
structure of the MIB, short descriptions of the table(s)
including usage of the table(s) for management and/or by
other MIB(s).
MIB definitions:
4. MIB syntax checking:
smilint -s -e -l 5 mibs/L2L3-VPN-MCAST-MIB 2>L2L3-VPN-MCAST-MIB.txt
mibs/L2L3-VPN-MCAST-MIB:63: [4] {hyphen-in-label} warning: named number
`rsvp-p2mp' must not include a hyphen in SMIv2
mibs/L2L3-VPN-MCAST-MIB:64: [4] {hyphen-in-label} warning: named number
`ldp-p2mp' must not include a hyphen in SMIv2
mibs/L2L3-VPN-MCAST-MIB:65: [4] {hyphen-in-label} warning: named number
`pim-asm' must not include a hyphen in SMIv2
mibs/L2L3-VPN-MCAST-MIB:66: [4] {hyphen-in-label} warning: named number
`pim-ssm' must not include a hyphen in SMIv2
mibs/L2L3-VPN-MCAST-MIB:67: [4] {hyphen-in-label} warning: named number
`pim-bidir' must not include a hyphen in SMIv2
mibs/L2L3-VPN-MCAST-MIB:68: [4] {hyphen-in-label} warning: named number
`ingress-replication' must not include a hyphen in SMIv2
mibs/L2L3-VPN-MCAST-MIB:69: [4] {hyphen-in-label} warning: named number
`ldp-mp2mp' must not include a hyphen in SMIv2
mibs/L2L3-VPN-MCAST-MIB:215: [5] {group-unref} warning: current group
`l2L3VpnMcastOptionalGroup' is not referenced in this module
mibs/L2L3-VPN-MCAST-MIB:4: [5] {import-unused} warning: identifier
`NOTIFICATION-TYPE' imported from module `SNMPv2-SMI' is never used
mibs/L2L3-VPN-MCAST-MIB:5: [5] {import-unused} warning: identifier
`Unsigned32' imported from module `SNMPv2-SMI' is never used
mibs/L2L3-VPN-MCAST-MIB:8: [5] {import-unused} warning: identifier
`NOTIFICATION-GROUP' imported from module `SNMPv2-CONF' is never used
mibs/L2L3-VPN-MCAST-MIB:11: [5] {import-unused} warning: identifier
`TruthValue' imported from module `SNMPv2-TC' is never used
mibs/L2L3-VPN-MCAST-MIB:11: [5] {import-unused} warning: identifier
`RowStatus' imported from module `SNMPv2-TC' is never used
mibs/L2L3-VPN-MCAST-MIB:12: [5] {import-unused} warning: identifier
`TimeStamp' imported from module `SNMPv2-TC' is never used
mibs/L2L3-VPN-MCAST-MIB:12: [5] {import-unused} warning: identifier
`TimeInterval' imported from module `SNMPv2-TC' is never used
mibs/L2L3-VPN-MCAST-MIB:15: [5] {import-unused} warning: identifier
`SnmpAdminString' imported from module `SNMP-FRAMEWORK-MIB' is never used
mibs/L2L3-VPN-MCAST-MIB:18: [5] {import-unused} warning: identifier
`InetAddress' imported from module `INET-ADDRESS-MIB' is never used
mibs/L2L3-VPN-MCAST-MIB:18: [5] {import-unused} warning: identifier
`InetAddressType' imported from module `INET-ADDRESS-MIB' is never used
5. REFERENCE clauses: Please use REFERENCE clauses liberally.
Wherever possible, provide references for objects used in
the MIB. The references will point to specific sections/
sub-sections of the RFCs defining the protocol for which the
MIB is being designed. It will greatly improve the readability
of the document.
6. IMPORTS clause
MIB modules from which items are imported must be cited and
included in the normative references.
The conventional style is
mplsStdMIB
FROM MPLS-TC-STD-MIB -- [RFC3811]
7. Please update the MODULE-IDENTITY. (There are no syntantic errors.)
7.1 CONTACT-INFO
Following the conventions (including indentation style) will
improve the readability. (e.g. RFC4382, RFC5132).
Will be good if it does not overflow into the next page.
7.2 REVISION clause: follow the convention recommended in RFC4181
sec 4.5
REVISION "200212132358Z" -- December 13, 2002
DESCRIPTION "Initial version, published as RFC yyyy."
-- RFC Ed.: replace yyyy with actual RFC number & remove this note:
7.3 OID assignment: follow the convention recommended in RFC4181
sec 4.5 i
replace
::= { experimental 99 } -- number to be assigned
by
::= { <subtree> XXX }
-- RFC Ed.: replace XXX with IANA-assigned number & remove this note
<subtree> will be the subtree under which the module will be
registered.
8. Specific MO and TC related comments.
L2L3VpnMcastProviderTunnelType ::= TEXTUAL-CONVENTION
STATUS current
DESCRIPTION
"Types of provider tunnels used for multicast in
BGP/MPLS L2 or IP VPN."
SYNTAX INTEGER { unconfigured (0),
rsvp-p2mp (1),
ldp-p2mp (2),
pim-asm (3),
pim-ssm (4),
pim-bidir (5),
ingress-replication (6),
ldp-mp2mp (7)
o Would be nice to align the enumeration labels with the
labels in the protocol document RFC 6514 unless there is
a good reason for not doing so. (You will have to take
care of the smi compilation errors too; '-' is not allowed ).
8.1 l2L3VpnMcastPmsiTunnelAttributeEntry OBJECT-TYPE
SYNTAX L2L3VpnMcastPmsiTunnelAttributeEntry
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"An entry in this table corresponds to an PMSI attribute
that is advertised/received on this router.
For BGP-based signaling (for I-PMSI via auto-discovery
procedure, or for S-PMSI via S-PMSI A-D routes),
they are just as signaled by BGP (RFC 6514 section 5,
'PMSI Tunnel attribute').
For UDP-based S-PMSI signaling for PIM-MVPN,
they're derived from S-PMSI Join Message
(RFC 6513 section 7.4.2, 'UDP-based Protocol')..
Note that BGP-based signaling may be used for
PIM-MVPN as well."
o Fix the ".." in "'UDP-based Protocol').." above.
o Please give the reference for this Table.
Is it- "PMSI Tunnel attribute" in RFC 6513 Sec.4 ?
"PMSI Tunnel attribute" in RFC 6514 Sec.5 ?
both?
Any other pointers?
8.2 l2L3VpnMcastPmsiTunnelAttributeFlags OBJECT-TYPE
SYNTAX OCTET STRING (SIZE (1))
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"For UDP-based S-PMSI signaling for PIM-MVPN, this is 0.
For BGP-based I/S-PMSI signaling, this is the Flags
field in PMSI Tunnel Attribute of the corresponding
I/S-PMSI A-D route."
::= { l2L3VpnMcastPmsiTunnelAttributeEntry 1 }
o Please confirm that the above is a complete enumeration of the
types of signalling.
o RFC 6514 Sec.5 says that the Flags field indicates
"Leaf Information Required". That is useful information.
Please include in the description.
8.3 l2L3VpnMcastPmsiTunnelAttributeId OBJECT-TYPE
SYNTAX OCTET STRING ( SIZE (0..37) )
MAX-ACCESS not-accessible
STATUS current
DESCRIPTION
"For UDP-based S-PMSI signaling for PIM-MVPN, the first
four or sixteen octets of this attribute are filled with
the provider tunnel group address (IPv4 or IPv6)..
For BGP-based I/S-PMSI signaling, this is the Tunnel Identifier
Field in PMSI Tunnel Attribute of the corresponding I/S-PMSI
A-D route."
o Check the size specifications. The specs above say it can be
all sizes 0..37. That is not clear from the DESCRIPTION clause.
o Fix the ".." in "(IPv4 or IPv6).." above.
o RFC 6514 Sec 5. PMSI Tunnel Attribute gives the Tunnel Identifiers
for mLDP, PIM-SM, PIM-SSM, BIDIR-PIM,Ingress Replication,MP2MP.
It appears that the sizes (range) for each case will be different.
Please clarify that, and if there are discrete sizes, specify
accordingly.
8.3 l2L3VpnMcastPmsiTunnelPointer OBJECT-TYPE
SYNTAX RowPointer
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"If the tunnel exists in some MIB table, this is the
row pointer to it."
o "some MIB table" : specify which MIB table.
o In what case will the tunnel exist and in what case will it not?
o What will be the behaviour if the above condition is not satisfied?
8.4 l2L3VpnMcastPmsiTunnelIf OBJECT-TYPE
SYNTAX RowPointer
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"If the tunnel has a corresponding interface, this is the
row pointer to the ifName table."
o DESCRIPTION looks incorrect. Please fix it. Do you want to say
this object points to the corresponding row in the ifTable?
o In what case does the TunnelIf exist and in what case will it not?
o What will be expected if the tunnel does not have a corresponding
interface?
9. The Security Considerations section does not follow the Security
Guidelines for IETF MIB Modules
http://trac.tools.ietf.org/area/ops/trac/wiki/mib-security.
Please fix.
10.ID-nits
10.1 Checking nits according to http://www.ietf.org/id-info/checklist :
---------------------------------------------------------------------------
** There are 4 instances of too long lines in the document, the longest one
being 3 characters in excess of 72.
10.2 Checking references for intended status: Proposed Standard
---------------------------------------------------------------------------
== Missing Reference: 'RFC 7117' is mentioned on line 76, but not
defined
'described in [RFC6513, RFC6514, RFC 7117] and other documents tha...'
11. There is another WIP MVPN-MIB in draft-ietf-bess-mvpn-mib-02.txt
MVPN-MIB has objects that refer to L2L3-VPN-MCAST-MIB.
Is there a good reason for not merging the 2 documents? I have not seen
any discussion or explanation on this. I may have missed it. Please
clarify or, give some pointers.
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