| Title: | DEChub/HUBwatch/PROBEwatch CONFERENCE |
| Notice: | Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7 |
| Moderator: | NETCAD::COLELLA DT |
| Created: | Wed Nov 13 1991 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 4455 |
| Total number of notes: | 16761 |
Can someone explain "user-settable rate limit broadcast and multicast"
in the DECbridge 900MX, e.g., how could it help prevent broadcast storm?
Faraday
| T.R | Title | User | Personal Name | Date | Lines |
|---|---|---|---|---|---|
| 1135.1 | NACAD::SLAWRENCE | Mon Jun 20 1994 19:09 | 12 | ||
You can specify a maximum rate at which particular multicast addresses
(or the broadcast address) will be forwarded. Then you specify which
multi/broad-cast filters are rate limited (a little pushbutton on the
filter display that has a clock on it).
The rate applies to all selected filters (you cannot specify different
rates for different filters).
The bridge will then keep a broadcast storm on one segment from
flooding others - some of the packets will get through, but not all.
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| 1135.2 | More on Rate Limiting | NACAD::KRISHNA | Tue Jun 28 1994 20:09 | 26 | |
When you enable the Rate Limiting on the bridge and set the Rate Limit
status on addresses or protocols, the bridge controls the number of
packets with the set addresses or protocols that it forwards. If the
Rate Limit is 400 pkts/sec, you will not see any 1 second interval
where there would be more than 400 pkts of the specified addresses or
protocols.
Rate Limiting is only applied to broadcast and Multicast addresses. If
you set Rate Limit on a protocol type, all multicasts/broadcast of the
protcol type would be rate limited.
When you have a bridge connected to multiple segments, which has rate
limiting enabled, it would prevent the propagation of a broadcast storm
which appears in one of its ports to the other ports. So it prevents
the broadcast storms in all segments except the originating segment.
Of course it has no control over the originating segment.
There are Rate Limit counters available per port that show how many
frames were address and protocol rate limited on that port.
Hope this helps,
Krishna
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