Cisco Active Network Abstraction Administrator’s Guide, 3.5
Page 4 Cisco Systems, Inc.
1.2 Sheer DNA Components The Sheer DNA system is comprised of several key components, as
described in the sections that follow.
1.2.1 Autonomous VNE
The Autonomous VNEs (Virtual Network Elements) are software entities
that run as a completely autonomous process within the Sheer DNA Units.
Each VNE is assigned to manage a single Network Element (NE) instance
using whatever southbound management interfaces the NE implements (e.g.
SNMP or Telnet). The Autonomous VNEs are the entities that maintain a live
model of each NE and of the entire network.
As the VNE loads, it starts investigating the NE and automatically builds a
live model of the NE, including its physical and logical inventory, its
configuration and its status. Following the device investigation, the VNEs
begin to negotiate with peering VNEs, which represent the peering NEs
determining the connectivity and topology at different layers. This model of
the network topology, device state and device inventory is constantly being
updated by the VNEs, which track every change that occurs in the NE or in
the network.
Messaging between VNEs is used for running different end-to-end flows, in order
to provide information for root cause and impact analysis, service path tracing and
more.
1.2.2 The Sheer DNA Servers
Sheer DNA uses two distinct server types, each performing different activities:
• Sheer DNA Gateway
• Sheer DNA Unit
Sheer DNA Gateway
The Sheer DNA Gateway serves as the gateway through which all clients,
including any OSS/BSS applications as well as the Sheer DNA clients can
access the system. The gateway is an extended Sheer DNA Unit. It enforces
access control and security for all connections and manages client sessions.
In addition it functions as a repository for storing configuration, network and
system events and alarms.