N-1-2-075.01 Internet Digest by Deborah Estrin, Internetworking: Research and Experience is a quarterly, refereed, journal published by Wiley (D. Comer, R. Droms, D. Estrin, and L. Svobodova are the Editors). In the last two issues of 1991 there were several papers of interest to the ISOC community. "BERGATE--Interconnection of MAP/TOP Networks via Broadband ISDN", by T. Luckenbach, GMD-FOKUS, describes a VMEbus system developed to support communication between distributed MAP/TOP networks by means of 140 Mbits/s channels provided by the Berkom test network. In addition, TCP/IP routing and end-system functionality is supported. "On the Efficient Implementation of Fair Queueing", by S. Keshav, AT&T Bell Laboratories, studies the data structures and algorithms for the efficient implementation of fair queueing. Fair queueing is a queue service discipline for routers and switches that has been shown to have several advantages over the traditional first-come-first-serve discipline. The paper presents a novel performance evaluation methodology and uses it to evaluate the relative merits of several alternate implementations. "Design and Evaluation of Inter-Domain Policy Routing Protocols", by L. Breslau and D. Estrin (University of Southern California), discusses inter-domain routing protocols in the context of three design parameters: location of routing decision, expression of policy, and algorithm used. Several routing architectures are described. The authors conclude that an architecture based upon source routing, a link state algorithm, and policy information in the link state advertisements is best able to support source-specific policies and special types of service. However, an architecture using a distance vector algorithm and hop by hop routing presents certain advantages when less policy control is needed. "Privacy-enhanced Electronic Mail", by M. Bishop, Dartmouth College, describes the mechanisms developed by the Internet Privacy and Security Research Group to provide security enhancements for electronic mail. The first set of mechanisms is a protocol to provide privacy, integrity, and authentication for electronic mail; the second is a certificate-based key management infrastructure to support key distribution throughout the internet. The paper describes and evaluates the mechanisms and discusses the reasons behind their selection.