topic Re: Multicast Mac-Addresses in Application Networking https://community.cisco.com/t5/application-networking/multicast-mac-addresses/m-p/70061#M802 <HTML><HEAD></HEAD><BODY><P>Here are some of the list of well-known MAC addresses used by the Catalyst Switches:</P><P></P><P></P><P>01-80-c2-00-00-xx -- Famous BPDU'S</P><P></P><P>01-00-00-0c-00-00 -- ISL</P><P></P><P>01-00-0c-cc-cc-cc --- CDP, DISL, DTP (Dynamic Trunk proto)- all of them use the same muliticast address, the difference is in the protocol id field.</P><P></P><P>CDP == PROTOCOL TYPE 0X2000</P><P>DTP == PROTOCOL TYPE 0X2004</P><P></P><P>The reason that all of them use the same multicast address is that the only kind of packets that are allowed to go thru on a blocked port (Spanning Tree) are CDP and BPDU's.</P><P></P><P></P><P></P></BODY></HTML> Mon, 24 Jun 2002 21:37:54 GMT 2002-06-24T21:37:54Z Multicast Mac-Addresses https://community.cisco.com/t5/application-networking/multicast-mac-addresses/m-p/70060#M801 <P>is somewhere a list of multicast-mac addresses which are used on catalyst switches for different protocols (cdp,disl,vtp,uplink fast,dtp,bvst+)</P><P></P><P></P> Mon, 24 Jun 2002 21:37:54 GMT https://community.cisco.com/t5/application-networking/multicast-mac-addresses/m-p/70060#M801 admin_2 2002-06-24T21:37:54Z Re: Multicast Mac-Addresses https://community.cisco.com/t5/application-networking/multicast-mac-addresses/m-p/70061#M802 <HTML><HEAD></HEAD><BODY><P>Here are some of the list of well-known MAC addresses used by the Catalyst Switches:</P><P></P><P></P><P>01-80-c2-00-00-xx -- Famous BPDU'S</P><P></P><P>01-00-00-0c-00-00 -- ISL</P><P></P><P>01-00-0c-cc-cc-cc --- CDP, DISL, DTP (Dynamic Trunk proto)- all of them use the same muliticast address, the difference is in the protocol id field.</P><P></P><P>CDP == PROTOCOL TYPE 0X2000</P><P>DTP == PROTOCOL TYPE 0X2004</P><P></P><P>The reason that all of them use the same multicast address is that the only kind of packets that are allowed to go thru on a blocked port (Spanning Tree) are CDP and BPDU's.</P><P></P><P></P><P></P></BODY></HTML> Mon, 24 Jun 2002 21:37:54 GMT https://community.cisco.com/t5/application-networking/multicast-mac-addresses/m-p/70061#M802 2002-06-24T21:37:54Z