Re: REVERSE_ASNENCODING
Dave Shield <[email protected]>
| Newsgroups | gmane.network.net-snmp.user |
|---|---|
| Message-ID | <[email protected]> |
2009/6/15 sanjaykumar <[email protected]>: > #define NETSNMP_USE_REVERSE_ASNENCODING 1 > #define NETSNMP_DEFAULT_ASNENCODING_DIRECTION 1 > Please somebody let me know what is ACTUAL use of this macro. It's concerned with the process of encoding the SNMP request into the packet that's actually sent out over the network. And in particular, with the handling of the multiple levels of wrapping that SNMP uses. Many of the encodings have the form "length data" where the first byte (or two bytes (or three bytes...)) indicates how large the following data will be. But this data may itself be the encoding of various other values - so we don't know how big it will be until *after* it's been encoded. And hence, we don't know whether the length field will need one, two or three... bytes. The simplistic approach is to assume that all lengths will need the larger size. But this is somewhat wasteful (and can run into problems with extra-large data that might need *more* than three bytes). So the trick that we use (take a bow, Mr Hardaker), is to encode the request starting at the very end, and work backwards. So we begin with the lowest-level data, and encode that. So now we know how big the encoded data is, and can use the correct representation for this length when encoding the next layer outwards. > Dees it explicitly required ? > If i will disable I have to disable both ?? It's not fundamental, no - you *could* turn it off if you really wanted. But why would you do that? It works much better this way. If you were to change anything, it would make more sense to remove support for "forward encoding", and *always* use the reverse mechanism. > how can I disable ? No idea - it's a daft thing to want to do! What are you trying to achieve here? Dave ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Net-snmp-users mailing list [email protected] Please see the following page to unsubscribe or change other options: https://lists.sourceforge.net/lists/listinfo/net-snmp-users