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Dear Sir:

Recently,i am studying "The Switch
Book"(bookstore:'WIERLY',author:'')and IEEE 802.1D.

First, in this "The Switch Book" book,page.103, it said that "any of
the protocols that use these address,the bridge must not forward or
flood frames sent to any reserved address" and the reserved address
are "01-80-c2-00-00-00 ,01-80-c2-00-00-01 ,01-80-c2-00-00-02
,01-80-c2-00-00-03 ,.....01-80-c2-00-00-0F ".
Second,in 802.1D 2003, 7.12.6 Reserved addresses:
"Frames containing any of the group MAC Addresses specified in Table
7-10 in their destination address field shall not be relayed by the
Bridge. They are configured in the Permanent Database. Management
shall not provide the capability to modify or remove these entries
from the Permanent or the Filtering Databases. These group MAC
Addresses are reserved for assignment to standard protocols, according
to the criteria for such assignments (Clause 5.5 of ISO/IEC TR
11802-2)." in Table7-10,there are some information about reserved
addresss which are "01-80-c2-00-00-00 ,01-80-c2-00-00-01
,01-80-c2-00-00-02 ,01-80-c2-00-00-03 ,.....01-80-c2-00-00-0F ".

But when i use PC and network analysis tools(such as Sniffer)to send
RSTP BPDUs(to pretend my PC is a switch),and to cpature frames from
CISCO2950. I disabled STP or RSTP or MSTP protocol(function) in all
VLAN which are exist in Cisco,i still captured RSPT BPDUs from CISCO.
Could someone please tell why Cisco doesn't follow the IEEE
standard,or some other reasons that switch isn't necessarily to follow
the standard?

Wade
Best Regardly 2003.12.16