Advertising a default route in BGP

There are four ways to distribute a default route in BGP.

Three of them, the network 0.0.0.0, the default-information originate and redistribution from another routing protocol, are all similar in the resulting effect: they will inject the default route into BGP RIB and it will be advertised to all BGP neighbors. The difference is in the origin of the default route that is injected into BGP. Specifically:

  • network 0.0.0.0 will inject the default route into BGP only if the default route is currently present in the routing table.
  • redistribution will inject the default route into BGP only if the default route is currently present in the routing table and if it has been learned by a specific source protocol we are redistributing from.
  • default-information originate causes the default route to be artificially generated and injected into the BGP RIB, regardlessly of whether it is present in the routing table. The newly injected default will be advertised to all BGP peers (because it now resides in the BGP RIB)

The fourth method:

  • neighbor X.X.X default-originate is similar to the default-information originate in that the default route is “artificially generated” (it does not need to be present in the routing table in order to make the advertisement effective)*.
  • However, the neighbor X.X.X.X default-originate is different from the the default-information originate in that the default route will be advertised only to this specific BGP neighbor and not to all existing BGP neighbors as with the previous approaches. The default route will not be installed in the BGP RIB of the router that is configured with the neighbor X.X.X.X default-originate command and so it won’t be generally advertised to all BGP neighbors.

*By doing the ‘default-originate’, you request a routerA (provider A) to send a route 0.0.0.0/0 via BGP out to RouterB (customer B).This is useful in many cases where customer B doesn’t really want toaccept a full BGP feed(for example in stub autonomous systems).

Building a SPS Solution

Using MangoES with 3/4g intergrated corporate connectivity for management & monitoring. 👌🏼

Lake Argyle – Sat and SSN

A quick install of Satellite Communications, using the Telsta iterra network and SSN (Silver Springs Networks) Access Points in remote WA. One of a few AP’s that have to be Sat connected due to there being no 3/4G. Nevertheless it worked as expected. These SSN AP’s operate on both 900 MHz and 2.4 GHz which increases the capacity and reliability of the meshed network, ultimately providing access and supporting Smart Meters, out bush.

Working in 40 degree heat with shade provided, courtesy of Horizon Power 👌🏼

SSN AP

UCS-E160D and CIMC

As part of a vWAAS deployment on a 3945-ISR-G2, my objective was to access the UCS-E server, initially the CIMC interface for the install of ESXi and then vWAAS, via the /29 address i’d allocated.

Here’s a much nicer look at that configuration.

interface GigabitEthernet0/0
 description [Link to 3850]
 ip address 172.22.39.65 255.255.255.248

interface ucse 4/0
 description [UCS-E Series CIMC Link]
 ip unnumbered GigabitEthernet0/0
 imc ip address 172.22.39.67 255.255.255.248 default-gateway 172.22.39.65
 imc access-port shared-lom console

interface ucse4/1
 switchport mode trunk

ip route 172.22.39.67 255.255.255.255 ucse4/0