Hello,
CEF stands for Cisco Express Forwarding, and it is a mechanism of organizing the routing table and the related frame rewrite information in a way that allows for very efficient and fast routing information lookup. CEF can be implemented either in software or using specialized hardware circuits. For more information about router switching paths including CEF, read the following document:
http://www.cisco.com/en/US/tech/tk827/tk831/technologies_white_paper09186a00800a62d9.shtml
An ASIC stands for "Application Specific Integrated Circuit". As the name suggests, an ASIC is a specialized piece of hardware circuitry designed to perform a particular operation in a highly efficient way. For example, you may have an ASIC that performs encryption and decryption. Or you may have an ASIC that is responsible for filtering frames based on their MAC addresses. An ASIC can be used, for example, to compute and verify checksums of frames, packets, perform NAT, compression and decompression of data, encode and decode video and audio, etc. ASICs are always optimized to perform a single particular operation, and hence they are not universal. That is why there is no single documentation on ASICs simply because there is no universal ASIC. General information exists, of course, e.g.:
http://en.wikipedia.org/wiki/Application-specific_integrated_circuit
Best regards,
Peter
