VSIZE (Size Virtual-Protocol)
S. O'Malley and L. Peterson. A Dynamic Network Architecture. ACM Transactions on Computer Systems 10, 2 (May 1992), 110--143.
VSIZE is a virtual protocol that multiplexes messages through N lower-level protocols based on the size of the message being sent. By default, VSIZE determines the maximum packet size that each lower level protocol can handle by performing a GETOPTPACKET control operation on the first N-1 lower protocols (the last lower protocol is assumed to have an infinite maximum packet size). VSIZE sends each message using the lower level protocol with the smallest index whose optimum packet size is greater than the length of the message.
VSIZE is in the ASYNC realm.
VSIZE passes participants to the lower protocols without manipulating them.
VSIZE forwards control operations to the ``largest message'' protocol.
VSIZE's lower protocols should be order by decreasing efficiency and increasing packet size.
VSIZE recognizes the following ROM options:
vsize/xxx cutoff C1 C2: Instantiation xxx of VSIZE should use a cutoff length of C1 bytes for its first down protocol and a cutoff value of C2 bytes for its second down protocol. This control operation allows the user of VSIZE to override the GETOPTPACKET. Note this operation does not check to see if the specified cutoff value is less than the maximum packet size of the lower level protocol.
Ed Menze