[FROG] Multiple routing tables and BGP

Julien RICHER julien at ywigo.fr
Mon Jun 17 03:40:08 EDT 2019

Hi FRR users,

We have a use case we don't know how to handle with BGP/FRR.

We need to share :

right side : a L3 network with dialup links
- without VRF
- with BGP in order to learn connected links

left side : 3 customers
- now : static routing without BGP
- futur : with BGP in order to announce their connected links and add redundancy

For now, we use multiple routing table and rules in order to isolate customers.

## Examples

# Customers interconnexions

# DialUP links pools
CustA pool
CustB pool

# Multiple routing tables
echo 302 custa >> /etc/iproute2/rt_tables
echo 303 custb >> /etc/iproute2/rt_tables

# Default route
ip route add default via dev eth0 table custa
ip route add default via dev eth0 table custb

# Rules for isolation
ip rule add from lookup custa
ip rule add from lookup custb

# 2 dialup link for CustA

CustA Link1 WAN =
CustA Link1 LAN =

CustA Link2 WAN =
CustA Link2 LAN =

# Our problem

This solution is good for a POC with static routing on customer's
side, but we need to use BGP with customers in order to :
- provide redundancy
- announce its connected dialup links to each customer

Since we don't use VRFs, announce connected links to customers is easy
with prefix-list (ex: ge 24 for custA).
But we don't understand how to not use static default route in our
routing tables and inject BGP routes learned from customers in each
routing table.

Is FRR able to inject peer's routes in a specific table without VRFs ?

If needed, we can move to VRF on customer side, but since dialup
network is not VRF aware, links routes are in vrf0 and we don't
understand how to handle it.

Is there a solution for this case ?
Maybe a route-map would permit to push learned routes of a peer in a
specific table ?

Thank you,

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