Glossary
GL-13
Cisco IOS XR Getting Started Guide
OL-10957-02
V
VCSEL vertical cavity surface emitting laser.
vm A vm file is a CiscoIOS XR software file that can be installed from ROM Monitor mode. A vm file is
typically used to install the CiscoIOS XR software when the software has not yet been installed or has
been corrupted.
VPN Virtual Private Network. Enables IP traffic to travel securely over a public TCP/IP network by
encrypting all traffic from one network to another. A VPN uses “tunneling” to encrypt all information
at the IP level.
W
WRED Weighted Random Early Detection. Queueing method that ensures that high- precedence traffic has
lower loss rates than other traffic during times of congestion.
X
XML Extensible Markup Language. A standard maintained by the World Wide Web Consortium (W3C) that
defines a syntax that lets you create markup languages to specify information structures. Information
structures define the type of information, for example, subscriber name or address, not how the
information looks (bold, italic, and so on). External processes can manipulate these information
structures and publish them in a variety of formats. XML allows you to define your own customized
markup language.
XML agent A process on the router that is sent XML requests by XML clien ts and is responsible for carrying out
the actions contained in the request and returning an XML response back to the client. The XML Agent
for CORBA is an example of an XML agent provided on th e Cisco CRS-1 router.
XML client An external application that sends an XML request to the router and receives XML responses to those
requests.
XML operation A portion of an XML request that specifies an operation that the XML client would like the XML agent
to perform.
XML operation
provider
The router code that carries out a particular XML operation including parsing the ope ration XML,
performing the operation, and assembling the operation XML response
XML request An XML document sent to the router containing a number of requested operations to be carried out .
XML response Th e response to an XML request.
XML schema An XML document specifying the structure and possible contents of XML elements that can be
contained in an XML document.