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Getipconf Usage Notes

Syntax

BGP-related flags

BGP-Related Flags

Description

-noBGP

If this optional flag is specified, BGP information will not be generated.

-ignore <ipaddress>

All IP addresses of the type 10.x.x.x, 127.x.x.x, and 192.168.x.x are local addresses. To prevent matching interfaces in one network with interfaces in another network, this optional ignore flag is provided. For example, if the user specifies the following:getipconf -ignore 192.168 -ignore 10. -ignore 127. *

Then all the links with addresses matching these patterns are commented out. However, if the addresses are all from the same network, this flag should not be included.

BGP Files Generated

In addition to the standard files like the spec, muxloc, and bblink files, the following are five output files related to BGP that are generated by getipconf: aclist.x, controllist.x, bgpobj.x, bgpnode.x, bgplink.x, bgpnbr.x, and subnet.x (assuming the runcode is x). Below is a brief explanation of the contents of these files:

  • aclist.x contains information about as-path, access-list, and community-list

  • controllist.x contains information about access-lists and prefix-list. The controllistobj.x file is a binary file.

  • bgpnode.x contains information for BGP speakers

  • bgplink.x contains information for BGP neighbors

  • bgpnbr.x is a text file that contains all information about neighbors.

  • bgpobj.x contains information about BGP neighbors shown in bgpnbr.x and route map structure. The bgpobj file is a binary file designed to save space and to speed up performance of the software. It is partially replaced by bgplink.x and bgpnode.x. How the program decides whether to read the bgpobj file or the bgplink and bgpnode file is explained below.

  • subnet.x is used to list those subnetworks originated by a particular router or AS node.

Corresponding Spec File Keywords

In the specification file, the keywords for the first four of these files will be listed as aclist, bgpobj, bgpnode, and bgplink. The bgpnbr file is for informational purposes only and is not included in the specification file.

For an example of the specification file entries related to BGP, see the following example:

Usage Note

Users need to comment out the specification of the bgpobj file in the specification file if they plan to edit BGP attributes manually. When loading the network, the rtserver (or bbdsgn) program reads the bgpobj file, if it is specified, ignoring the bgpnode and bgplink files. However, if the bgpobj file is not specified or it is commented out, rtserver will read the bgpnode and bgplink files instead. When saving the network, all three files: bgpobj, bgpnode and bgplink will be saved.

dparam File

The following are some of the BGP-related parameters in the dparam file that you may want to change. They can also be changed through the Tools > Options menu as described in BGP Options .

  • If IBGP policies are used in the network to influence routing, set the chkIBGPflag parameter to 1. By default, it is set to 0 to speed up routing.

  • The simskipAS parameter is set to 1 by default, meaning that AS nodes and links will not be brought down in an exhaustive failure simulation performed from Simulation > Predefined Scenarios. If you wish to check the impact of an AS node or AS link failure on traffic routing, change the value to 0. Note, however, that if there are a lot of AS nodes, this may greatly increase the time it takes to perform the simulation. To indicate that only a subset of the AS nodes should be failed and the rest of the AS nodes should be ignored, mark the AS nodes or AS links to ignore with the FAIL=0 flag. This parameter can be set in the Modify > Elements > Nodes, Design properties tab (or add it to the end of the muxloc file entry) or Modify > Elements > Links, Properties tab (or add it to the miscellaneous field of the bblink file entry).

  • The IGPoverride option is false (0) by default, meaning that for external paths, BGP will be treated as having a higher administrative distance/preference than the IGP such as OSPF. If this is not the case, this parameter can be set to true (1).

bgpnode format

bgplink format

Note:

Due to the complexity, peer group and policy are not defined in these two files now.

aclist format

bgpnbr file

The bgpnbr file is for information purposes and is not read into the specification file. See the following table for a description of the fields in the bgpnbr file.

Field

Description

Status

Status of the neighbor, either up or down

AS

The AS number of the BGP speaker

Intf

The IP address of the interface used to connect to the neighbor

Node

The name of the BGP speaker

Z_AS

The AS number of the neighbor

Z_intf

The IP address of the interface on the neighbor router

Z_Node

The name of the neighbor

PeerGroup

The peer group name if it is applicable

RRclient

The indicator to indicate whether the neighbor is a route reflector client or not

Cluster

The cluster ID if it is applicable

Multihop

The optional TTL (Time to Live) number from the IOS command: neighbor {ip-address | peer-group-name} ebgp-multihop [ttl]

LocalPref

The Local Preference attribute

Weight

The weight attribute

Med

The Multi-Exit Discriminator attribute

InPolicy

The names of policies for incoming routes

OutPolicy

The names of policies for outgoing routes

ASs that are outside of the network and have EBGP peering relationship with BGP speakers of the network are represented by ASnodes in the muxloc file (the node file of Paragon Planner).

Subnet File

A snippet of a sample subnet file is shown here. The address/mask field denotes the subnetwork originated by the node. The misc field is used to specify any BGP attributes associated with the subnetwork.