[SOLVED] OSPF + PPPoE + Subnet Public Class C

RouterOS Forwarding Protocols
1

Hi everyone! I have some questions about OSPF areas and PPPoE. Im training with a virtual lab using GNS3 before deploy it in a real enviroment.

We have the next scenario:

Our network are in bridge mode with only one router (Gw Router) acting as a PPPoE Server for all clients.

I was configured the basic OSPF network showed in the above diagram.

We have some public class C networks given us by our ISP configured on “Gw Router” in “ether2” interface… as example:

  • Pool A: 60.60.60.0/24
  • Pool B: 70.70.70.0/24
  • Pool C: 80.80.80.0/24
  • Pool D: 90.90.90.0/24

I want to split a class C networks we have in multiple subnets and use one of these subnets for PPPoE clients in OSPF environment.

For example I want to take the “Pool D” and divide it into multiple subnets / 28 and use the 90.90.90.240/28 subnet for OSPF

I made a basic configuration and i have full ip connectivity between all OSPF routers that make up the network, but can not get customers “PPPoE A” and “B PPPoE” go on internet

I explain the basic configuration of OSPF on each router to see if you can help me get to solve my doubts.

R1:

/ip addresses
ether1: 172.16.0.2/24
ether2: 10.0.0.1/30
loopback: 10.255.255.1/32

/ip route
Dst: 0.0.0.0/0  - Gateway: 172.16.0.1

/routing ospf interface
ether2, type=default

/routing ospf instance
router-id=10.255.255.1, distribute-default=as type 1, redistribute-connected=as type1

/routing ospf networks
network=10.0.0.0/30, area=backbone

R2:

/ip addresses
ether1: 10.0.0.2/30
ether2: 10.0.0.5/30
loopback: 10.255.255.2/32

/routing ospf interface
ether1, type=default
ether2, type=default

/routing ospf instance
router-id=10.255.255.2, distribute-default=never, redistribute-connected=as type1

/routing ospf networks
network=10.0.0.0/30, area=backbone
network=10.0.0.4/30, area=backbone

R3:

/ip addresses
ether1: 10.0.0.6/30
ether2: 10.100.100.1/24
loopback: 10.255.255.3/32

/routing ospf interface
ether1, type=default
ether2, type=broadcast, passive=yes

/routing ospf instance
router-id=10.255.255.3, distribute-default=never, redistribute-connected=as type1

/routing ospf networks
network=10.0.0.4/30, area=backbone
network=10.100.100.0/24, area=pppoe
network=90.90.90.240/28, area=pppoe

/routing ospf areas
0.0.0.0, name=backbone, type=default
0.0.0.1, name=pppoe, type=stub

/routing ospf areas range
90.90.90.240/28, area=pppoe

Would it be correct all this configuration or I’m making mistakes?

How would you configure the OSPF network and bridge network to assign customer “PPPoE Client A” customer “PPPoE B” a public IP address within the range 90.90.90.240/28 and had internet access through the main router that is within the bridged network?

Thanks!

2

Your setup does not make sense with what you are saying - you say you only have one PPPoE server but your diagram shows two? It looks like it is not fully bridged because you show an area border router with a PPPoE stub area.

This also just seems a bit of a bizarre layout - I would not connect customers on the same broadcast domain as your links to other routers.

Have you considered using something like MPLS/VPLS to carry your PPPoE instead of bridging everything? I don’t know how big this network is, but with large bridged networks it tends to be riskier and more difficult to find issues.

3

Thanks for your answer mducharme!

Our actual network is fully bridged (left diagram part only) with only one Gateway router & PPPoE Server. Default gateway for all class C pools on this router is 50.50.50.1 (ISP Router)

I want to deploy the right diagram part in a lab for better understand how OSPF works before change entire network to routed.

4

R3 won’t advertise the two subnets you have set up because no interface has an IP address on these two subnets:

network=10.100.100.0/24, area=pppoe
network=90.90.90.240/28, area=pppoe

On R3, create a second bridge with no ports (like loopback), for holding the PPPoE addresses, with an address assigned on those two subnets (ex. 10.100.100.1/24 and 90.90.90.241/28).

5

Thanks for your reply!

Ok, I will try this. thanks! :wink:

6

I got it!

The problem was in my PC that are using GNS3 under NAT…

(Internet Router)–192.168.0.1---------------192.168.0.2–(Laptop)–192.168.137.1-----------------192.168.137.2–(ASBR in GNS3)

I test my diagram in a real enviroment and works perfectly!! jejeje

Thanks for all!