Bank BCA wants to subscribe MPLS Link over
all of the branches in indonesia using
L3VPN/VPRN through our backbone network.
The branch offices are 8 : Jakarta1, Jakarta2,
Bogor, Bekasi, Surabaya, Malang, Madiun,
Datacenter is located in Tangerang City
All BCA Routers connected to each 9 PEs.
One of VPRN/L3VPN problem is, to comply with such
topology, and to connect all client routers, iBGP
Peering on the PEs must be fully meshed on each
This could become a painful jobs when we add one or
more network into current vrf, we need to reconfigure
all related vrf PE, to do full mesh iBGP peering.
Peer formula = n(n-1)/2,
n stands for number of routers,
For example 9 routers, will need 41 peer connection
10 routers, will need 45 peer connection
25 routers, will need 300 peer connection
50 routers, will need 1225 peer connection
Full Mesh iBGP Peering
iBGP Peering in huge
VRF is such a mess and
Route Reflector / RR are an alternative way to
provide full meshed iBGP peers. One or more
routers configured as a route reflector, while
the remaining iBGP routers are configured as
clients and peer only with route reflector
forming a Route Reflector Cluster. This
reduces the number of connections required
to the number of clients. Routing updated
received by a client are sent to the Route
Reflector and it will forward to other clients in
iBGP Peering with Route Reflector
RR Reflects all BGP
received, towards all
of the neighbor
RR Deployment Methods
Option 1 involves using the PE router as the VPNv4 RR as well.
◦ This type of setup is not recommended due to additional
constraints of memory and CPU imposed on the PE router
that acts as RR, which is handling both the functions of
providing services to client edge routers as well as reflecting
routes to several other PEs in the same MPLS domain.
Option 2 involves using the P router as an RR for both IPv4 and VPNv4.
◦ The P router handles not only the function of route reflection
for IPv4 and VPNv4 routes, but also performs data
forwarding operations for IPv4 and VPNv4 traffic.
◦ This scenario may not scale well in large MPLS VPN
environments due to memory and CPU constraints imposed
on the RR that not only provides IPv4 and VPNv4 routing
services but also data forwarding functionality.
Option 3 involves using a P router as a RR only for VPNv4.
◦ This implementation can be used in large-scale MPLS VPN
environments in which the provider network wants to
isolate IPv4 functionality on the VPNv4 RR.
Option 4 involves a dedicated router performing the function of
reflecting IPv4 and VPNv4 routes. The router does not perform
any data forwarding functions.
◦ This scenarios also increases the provider's operational
costs because the provider has to dedicate routers RRs
for IPv4 and VPNv4 prefixes as well as ensure their PE
routers have physical connectivity with each other for
data forwarding functionality or are connected to a
dedicated P router, which perform data forwarding
Option 5 involves a dedicated router as a RR for only VPNv4
routes and not for data forwarding. Like the last option, there
is considerable savings in CPU and performance improvements
can be realized but at the cost of additional routers providing
provider router functionality and increased cost in providing
physical connectivity between PE and P routers.
Option 6 involves partitioned RRs, which is primarily in large-
scale environments in which using a dedicated VPNv4 RR does
not scale to the demands of a large provider carrying a large
number of VPNv4 prefixes.
For this case, IPv4 BGP
Peering is fully meshed
(light red color)
but VPNv4 BGP peering is
configured through RR
Install / Add dedicated
RR into current Network
IPv4 BGP Peering is fully
meshed (light red color)
but VPNv4 BGP peering is
configured through dedicated
BGP VPNv4 peering for each
VRF are divided to different
RR, to reduce the load of
Due to lack of operational budget, team will use
Option 1 for RR Deployment Method. This
solution is Temporary, and is proposed on next
budget to bought additional dedicated RR Routers
to do the job.
Positive impact :
◦ Simplify BGP Configuration
◦ BGP Peering kept Redundant
◦ It also makes BGP process low on all non RR PE Routers.
◦ Easy to do expansion for the current VRF
Negative impact :
◦ High BGP Process loads on the RR