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Multicast Address Ranges


– is the range used

– – All Hosts

– – All Routers


GLOP Addressing

– GLOP addressing is used to give anyone with their own registered public AS number their own globally unique multicast IP address range.

– is the reserved GLOP range.

– 233.x.x.0/24 is the actual address you use, where x.x is the 2 bytes of your AS number.  If your AS was 54321, convert it to hex = D431.  Here D4 is the first byte, and 31 is the second byte.  D4 into Decimal is 212, and 31 into decimal is 49. So your range is

– The drawback is that it only works with 2 byte AS numbers

– GLOP doesn’t stand for anything, it’s just called GLOP


Administratively Scoped Addressess

– is the reserved range

– IP addresses in this range should be filtered on the edge of the administrative boundary

– This range of IP’s are only guaranteed to be unique within the administrative boundary (eg, within the BGP AS)


Source Specific Multicast

– is the reserved range for SSM

– Used to identify exactly what source & group a device wants to receive multicast traffic for



– is the range used


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