Specifications

OmniAccess 5510 USG - Release Notes
September 2010
WAN Protocols
HDLC
Layer 2 of the OSI model is the data link layer. One of the most common layer 2 protocols is the
High-level Data Link Control (HDLC) protocol. In fact, many other layer 2 protocols are based on
HDLC, particularly its framing structure. OA5510-TE supports only Cisco HDLC
Frame Relay
FR is a WAN protocol that operates at the physical and data-link layers of the OSI reference model.
This protocol was originally designed for use across ISDN interfaces but today it is used over a
variety of other network interfaces as well.
PPP
The PPP protocol emerged as an encapsulation protocol for transporting IP traffic over point-to-point
links. PPP also established a standard for the assignment and management of IP addresses, network
protocol multiplexing, link configuration, link quality testing, error detection and option negotiation
for such capabilities as network layer address and data compression. PPP supports these functions by
providing an extensible LCP and a family of NCPs to negotiate optional configuration parameters and
facilities. PPP supports IP through IPCP.
PPPoE
PPPoE (Point-to-Point Protocol over Ethernet), is a network protocol for encapsulating Point-to-Point
Protocol (PPP) frames inside Ethernet frames. Ethernet networks are packet-based and have no
concept of a connection or circuit and also lack basic security features to protect against IP and MAC
conflicts and rogue DHCP servers. By using PPPoE, users can virtually "dial" from one machine to
another over an Ethernet network, establish a point to point connection between them and then
securely transport data packets over the connection. OmniAccess 5510 USG supports PPPoE client
functionality on the Fast Ethernet and ADSL ports.
MLPPP
MLPPP is an extension to PPP.
• OmniAccess 5510 USG supports RFC 1990 (MLPPP Protocol) without necessarily
conforming to all the optional items mentioned in the specification.
• Specifically, the system supports the logical aggregation, into a configured MLPPP bundle of
Serial interfaces, etc. This bundle behaves like a virtual IP interface.
• Multiple MLPPP bundles may be statically configured on the system. MLPPP protocol
negotiation or data reaching the system on an unconfigured interface are dropped. Bundles
cannot be deleted, but can be shutdown and thereby made unusable.
• Without any QoS configuration applied on the MLPPP bundle, the packet distribution across
the MLPPP member links within a bundle is handled in a weighted round robin fashion, the
weight being the bandwidth of the links.
• Authentication optionally happens at each member link, and is supported through PAP,
CHAP or EAP as configured.
• IP routing protocols as well as policies such as ACL, NAT, IDS, IPsec, QoS and so on may
be applied on the bundle.
• The default MTU is 1500 on an MLPPP bundle interface. That makes the MRRU (Maximum
Received Restructured Unit) value to 1506 that accounts for the six extra bytes of the MLPPP
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