3Com 11.1 manual Approved Dram, SIMMs, New Features, DPE 40 module

Approved DRAM SIMMs 11

Approved DRAM	Table 2 lists 3Com–approved vendors of the 32 MB DRAM SIMM for upgrading
SIMMs	the DPE 40 module.
	Table 2 3Com–approved DRAM SIMMs
	Size	Vendor and Description	Part Number
	32 MB	NEC	MC428000A32B-60
	72-pin 8Mx32 60 ns page mode	Toshiba	THM328020S-60
		Toshiba	THM328020B5-60
New Features	This section describes new features in software version 11.1 for the
	NETBuilder II, SuperStack II, and OfficeConnect NETBuilder bridge/routers.
VPN Features	Layer Two Tunneling Protocol
	Layer Two Tunnelling Protocol (L2TP) is a standards-based protocol created from
	combining two similar but incompatible proprietary tunneling protocols,
	Point-to-Point Tunneling Protocol (PPTP) and L2F (Cisco’s tunneling protocol). L2TP

is primarily used in Virtual Private Networking (VPN) environments and allows the creation of a tunnel between a remote site and a central site in order to transport Layer 3 multiprotocol traffic (such as IP, IPX, and AppleTalk) over a public IP network.

L2TP is a connection-oriented protocol that provides flow control, packet sequencing, and retransmission capabilities. The transport network of L2TP can be any packet-oriented network, but for this release, UDP/IP is the supported transport network type. Similar to a PPTP connection, L2TP puts the data inside a PPP frame and then encapsulates the frame with a UDP/IP header.

A notable difference between L2TP and PPTP is that PPTP precedes Layer 3 frames with a GRE header and forwards them to IP via TCP, but L2TP precedes Layer 3 frames with its own protocol header (which looks similar to a GRE header) and forwards them to IP via UDP.

From a security standpoint, L2TP by itself, like PPTP by itself, does not provide data encryption, authentication, or integrity functions (other than those that exist with IP and PPP) that are critical to maintaining VPN privacy. Also, L2TP does not provide a mechanism for key management. These areas are for further development.

IPX RAS

With this release, the NETBuilder RAS service has been extended to include IPX RAS support. The IPX RAS functionality implemented is Proxy routing (unlike IP RAS which can be either LAN Extension or Proxy Routing). The NETBuilder bridge/router routes IPX traffic between the external IPX network and the internal “Proxy” IPX network. All the IPX clients share a single Proxy IPX network and sit logically on the Proxy IPX network. Forwarding IPX traffic to clients is based on the Node ID (MAC address) of each client.