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Krzysztof suggested I forward my response to the
reflector...
Enjoy!
--
Mike
Geipel From: Mike Geipel Sent: Wednesday, February 16, 2005 12:49 PM To: 'Krzysztof Dudzinski' Subject: RE: [STDS-802-16] [NETMAN] What is "BS Sector Mac Address" role Hi Krzysztof,
Yes, I saw the message from Jeff, but I wasn't
aware of that connection either.
It would certainly be convenient for BSID to be
manufacturer-supplied MAC address, especially in 802.16e...
Looking at the spec ...
... if BSID is issued by operator, it cannot, in
general, be a MAC address.
In 802.16-2004, section 6.3.2.3.2:
This suggests that the BSID is unique to basestation,
not necessarily per-sector.
The only place where I saw the right semantics WRT
sectors, was in descriptions of Sector ID in compressed DL-MAPs, SCa on page 403
section 8.2.1.8.1, and OFDMA on page 549, section 8.4.5.6.1.
We should probably define the following in the
Corrigenda Glossary:
Base Station Identifier
Operator Identifier
Sector Identifier
Although the sizes are right, there is
no statement that the most significant 24 bits are an IEEE OUI, and that
least significant 24 bits are guaranteed unique (for that operator). Even
if we were to fix the Corrigenda to say so, I'm not sure how to enforce
this. The consequences of not getting this right could lead to really bad
forwarding behavior in certain deployments.
If BSID is manually
issued by operators, I would likely argue that it is not the
ifPhysAddress.
I'm not sure I understood the context for your other
question about interface port:
- I would think that each sector should
be considered a separate port as defined in RFC1493
(BRIDGE-MIB)
- Each downlink channel should be a separate
interface, as defined in RFC2863 (IF-MIB)
I think it would be prudent for the 802.16f spec to
define how interfaces are stacked, according to RFC2863 (and possibly
RFC2864).
I hope this helps.
--
Mike
Geipel From: Krzysztof Dudzinski Sent: Wednesday, February 16, 2005 7:32 AM To: Mike Geipel Subject: RE: [STDS-802-16] [NETMAN] What is "BS Sector Mac Address" role Mike,
Thanks for this.
Our plan is to
provide MacAddresses as specified in the MIB document. But this triggers some
more questions and leads to confusion. We may need to clarify the language used
in MIB document to be more specific. Here is an example of two. Do you have an
opinion about that?
- What is the relationship between BSID and BS (Sector) Mac
Address? Jeff Mandin comented about it but I don't see how we can use BSID as a
PhysAddress in ifTable. Mac Address is guaranteed unique and BSID not yet. Mac
Address is allocated by manufacturer, BSID by user
(operator).
- Where is the interface port we assign PhysAddress to? It
is easy with Ethernet but our .16 interface port is rather virtual, isn't
it?
Regards,
Krzysztof
From: Mike Geipel Sent: 13 February 2005 22:28 To: Krzysztof Dudzinski Subject: RE: [STDS-802-16] [NETMAN] What is "BS Sector Mac Address" role All SNMP implementations are required to conform to
RFC1213.
The RFC1213-MIB defines a textual convention for
PhysAddress ::= OCTET STRING.
It also defines ifPhysAddress OBJECT-TYPE SYNTAX
PhysAddress ::= { ifEntry 6 }.
The
latest version of the IF-MIB [RFC2863] does not change this, so this field
should be there (whether it is populated or not).
Conceptually, each MAC SAP should (by definition) have a MAC
address.
So, if
there is no SAP needed for a given interface, I suppose it can still bridge
frames without a unique MAC address.
There are,
however, pragmatic reasons to specify a MAC address for each
ifEntry.
In
answer to question (1):
Without a MAC address defined for each interface, Network Management
software will be unable to auto-discover the layer-2 topology accurately using
SNMP. (NNM, for example, uses RFCs 1493, 1515, 2108 for this
purpose.) Managed devices that populate their bridge tables, can then
be interrogated by management software for each
interface.
In
802.1D-2004, Section 6 states that "Mac Bridges interconnect the separate IEEE
802 LANs that compose a Bridged Local Area Network by relaying and filtering
frames between separate MACs of the bridged LANs." By this definition, I'd
argue that the BS is a "Mac Bridge" with at least
one network interface (802.3/Ethernet?) and at least one RF interface
(802.16 sector).
(The
Corrigenda now seems to mandate BS support for both Ethernet CS and
IP-over-Ethernet CS.)
In
802.1D-2004, Section 7.12.2 states that:
"The individual MAC Entity associated with each Bridge Port shall
have a separate individual MAC Address." And this is reiterated in Section
A., item ADDR-1.
BTW,
why not? MAC addresses are cheap. Once you've paid for a mechanism
to serialize for a single MAC address (like the BS Ethernet interface
that must have a SAP), it is easy to derive (say) ten more MAC addresses in a
block.
--
Mike
Geipel From: Krzysztof Dudzinski [mailto:KDudzins@AIRSPAN.COM] Sent: Friday, February 11, 2005 1:15 PM To: STDS-802-16@LISTSERV.IEEE.ORG Subject: [STDS-802-16] [NETMAN] What is "BS Sector Mac Address" role Hi All, As described “802.16_2004_TGF.pdf,
draft2, section 9.3.2.2” we decided to manage wireless man “BS Sectors” as
network interface. As such there is one row defined in the interface table
(ifTable) per “BS Sector” along with required attributes e.g. ifType
(propBWAp2Mp), IfPhysAddress (Mac Address of BS Sector) etc.
Two questions
arise: 1. Can anybody
think of the scenario where the Mac Address of “BS Sector” would be actually
used? 2. Can the
ifPhysAddress be filled with zero length octet string as suggest the description
of this object in the IF-MIB (see extract below) if standard doesn’t define the
use of it? Unlike SS Mac Address the Mac
Address of BS (Sector) is not defined in the standard 802.16-2004 at all. The BS
Mac Address is mentioned in the 802.16e/D5a in the context of Neighbor
advertisement message. But in this context it is not sure what Mac Address the
document refers to (what type of interface in the interface
table). Nevertheless the issue is with
802.16f MIB, which is designed for fixed operation. Extract form
IF-MIB: “ ifPhysAddress
OBJECT-TYPE
SYNTAX PhysAddress
MAX-ACCESS read-only
STATUS current
DESCRIPTION
"The interface's address at its protocol sub-layer.
For
example, for an 802.x interface, this object
normally
contains a MAC address. The interface's media-specific
MIB
must define the bit and byte ordering and the format of
the
value of this object. For interfaces which do not have
such
an address (e.g., a serial line), this object should
contain
an octet string of zero length." ::= {
ifEntry 6 } ” Regards, Krzysztof
Dudzinski Airspan
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