This post will shows applications of BGP Community.  It doesn't show deep description about BGP Community.  BGP communities are tags, or attributes that can be attached to BGP prefixes announcement.  Based on that community, policy can be define to do something to that routes.  BGP Communities are descibed in RFC 1997.  According to RFC 1997, BGP Communities describe as a group of destinations which share some common property.  Each autonomus system administrator may define which communities a destination belongs to.  By default, all destinations belong to the general Internet community.  BGP Community have 32 bit value.

Cisco has support EIGRP as PE CPE routing protocol in MPLS VPN.  It is just like another routing protocol using for PE CPE roituing protocol.  The mechanism is common.  EIGRP in PE talk with EIGRP in CPE to exchange routing, then routing receive from CPE is redistribute to MP BGP (multi protocol BGP) running under address family configuration.  EIGRP receive all VPN routing from reditributing form MP BGP (multi protocol BGP) running under address family configuration.

Peer group in a set of BGP neighbor that share some policy.  Policy that can be the same, for example, route-map, filter-list, prefix-list, update-source, route-reflector client.  Peer group can reduce cpu process consumption, also configuration effort.

This procedure will explain how to recover JunOS password.

Olive is PC running JunOS not in Juniper machine. Not like Cisco IOS that have Dynamips as ready to use IOS simulator, there is no ready to use JunOS simulator yet.