A lab which configures a computer network with internal border gateway protocol. Device configurations and other diagnostic information can be found in the corresponding folders.
Background information on lab concepts can be found here: https://101zh.github.io/networking/
- Purpose
- Lab Summary
- Topology
- Address Table
- Device Overview
- ICMPv4 Traceroute Across Network
- ICMPv6 Traceroute Across Network
- R1 IPv4 Routing Table
- R1 IPv6 Routing Table
- Copyright
The purpose of this lab is to use Internal Border Gateway Protocol (iBGP) to share routes in and out of an autonomous system (AS) by establishing iBGP neighborships. Additionally, eBGP will be used to share route information between the other two AS’s. As a part of this lab, knowledge about using route-reflectors, declaring iBGP neighbors, and using an interior gateway protocol (IGP) to help BGP packets get navigated between iBGP neighbors will be integral to setting up iBGP. For eBGP, skills about how to redistribute routes and how to use eBGP to route between AS’s will be important for this lab.
In this lab 3 AS’s were set up with eBGP connecting the 3 AS’s together. There are two host devices that are PCs and there are seven 4321 routers that are connected via ethernet. To allow host devices to communicate with each other, the routers needed IPv6 and IPv4 routes to redistribute in and out of eBGP. Additionally in the 2nd AS, iBGP is used to provide network connectivity between AS 1 and AS 3 with EIGRP serving as the routing protocol for the 2nd AS.
In the topology, R7—the router in the middle of the 2nd AS—acts as a route-reflector to neighbors: R3 and R4. This allows R7 to receive routes from R3 and R4, so that connectivity can be established between the 2 AS’s. And when R7 receives routes, it will send updates to R3 and R4, which will provide end-to-end connectivity for the PCs.
These are the topologies for both IPv4 and IPv6, each link is labeled with the network number and subnet mask of the link. Then each interface is labeled with the 4th octet of the usable IP address within the subnet of that link.
Additionally, the PCs can have any IP that is within the subnet of the link that they are on. DHCP is not setup.
| Device Name | Interface | IPv6 Address | IPv4 Address | Subnet Mask |
|---|---|---|---|---|
| R1 | G0/0/0 | 1:20::1/64 | 10.0.20.1 | 255.255.255.0 |
| R1 | G0/0/1 | 1::1/64 | 10.0.0.1 | 255.255.255.0 |
| R2 | G0/0/0 | 1::2/64 | 10.0.0.2 | 255.255.255.0 |
| R2 | G0/0/1 | 2::1/64 | 192.168.0.1 | 255.255.255.0 |
| R3 | G0/0/0 | 2::2/64 | 192.168.0.2 | 255.255.255.0 |
| R3 | G0/0/1 | 1:1::1/64 | 10.0.1.1 | 255.255.255.0 |
| R4 | G0/0/0 | 1:2::2/64 | 10.0.2.2 | 255.255.255.0 |
| R4 | G0/0/1 | 2:1::1/64 | 192.168.1.1 | 255.255.255.0 |
| R5 | G0/0/0 | 2:1::2/64 | 192.168.1.2 | 255.255.255.0 |
| R5 | G0/0/1 | 1:3::1/64 | 10.0.3.1 | 255.255.255.0 |
| R6 | G0/0/0 | 1:3::2/64 | 10.0.3.2 | 255.255.255.0 |
| R6 | G0/0/1 | 1:30::1/64 | 10.0.30.1 | 255.255.255.0 |
| R7 | G0/0/0 | 1:1::2/64 | 10.0.1.2 | 255.255.255.0 |
| R7 | G0/0/1 | 1:2::1/64 | 10.0.2.1 | 255.255.255.0 |
This Topology Consists of...
- Seven 4321 routers running Cisco IOS XE Software, Version 16.9 Universal K9
C:\>tracert 10.0.30.2
Tracing route to DESKTOP-66QHS53 [10.0.30.2]
over a maximum of 30 hops:
1 <1 ms <1 ms <1 ms 10.0.20.1
2 <1 ms <1 ms <1 ms 10.0.0.2
3 <1 ms <1 ms <1 ms 192.168.0.2
4 1 ms <1 ms <1 ms 10.0.1.2
5 <1 ms <1 ms <1 ms 10.0.2.2
6 1 ms <1 ms <1 ms 192.168.1.2
7 1 ms 1 ms 1 ms 10.0.3.2
8 2 ms 1 ms 1 ms DESKTOP-66QHS53 [10.0.30.2]
Trace complete.C:\>tracert 1:30::2
Tracing route to 1:30::2 over a maximum of 30 hops
1 <1 ms <1 ms <1 ms 1:20::1
2 1 ms <1 ms <1 ms 1::2
3 1 ms <1 ms <1 ms 2::2
4 1 ms 1 ms <1 ms 1:1::2
5 1 ms <1 ms <1 ms 1:2::2
6 2 ms 1 ms <1 ms 2:1::2
7 1 ms 1 ms 1 ms 1:3::2
8 1 ms 1 ms 1 ms 1:30::2
Trace complete.Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
3.0.0.0/32 is subnetted, 1 subnets
O E2 3.3.3.3 [110/10] via 10.0.0.2, 01:14:33, GigabitEthernet0/0/1
4.0.0.0/32 is subnetted, 1 subnets
O E2 4.4.4.4 [110/10] via 10.0.0.2, 01:12:41, GigabitEthernet0/0/1
10.0.0.0/8 is variably subnetted, 8 subnets, 2 masks
C 10.0.0.0/24 is directly connected, GigabitEthernet0/0/1
L 10.0.0.1/32 is directly connected, GigabitEthernet0/0/1
O E2 10.0.1.0/24 [110/10] via 10.0.0.2, 01:14:33, GigabitEthernet0/0/1
O E2 10.0.2.0/24 [110/10] via 10.0.0.2, 01:12:41, GigabitEthernet0/0/1
O E2 10.0.3.0/24 [110/10] via 10.0.0.2, 01:12:41, GigabitEthernet0/0/1
C 10.0.20.0/24 is directly connected, GigabitEthernet0/0/0
L 10.0.20.1/32 is directly connected, GigabitEthernet0/0/0
O E2 10.0.30.0/24 [110/10] via 10.0.0.2, 01:12:41, GigabitEthernet0/0/1
O 192.168.0.0/24 [110/2] via 10.0.0.2, 01:14:37, GigabitEthernet0/0/1
O E2 192.168.1.0/24 [110/10] via 10.0.0.2, 01:12:41, GigabitEthernet0/0/1
IPv6 Routing Table - default - 13 entries
Codes: C - Connected, L - Local, S - Static, U - Per-user Static route
B - BGP, R - RIP, I1 - ISIS L1, I2 - ISIS L2
IA - ISIS interarea, IS - ISIS summary, D - EIGRP, EX - EIGRP external
ND - ND Default, NDp - ND Prefix, DCE - Destination, NDr - Redirect
O - OSPF Intra, OI - OSPF Inter, OE1 - OSPF ext 1, OE2 - OSPF ext 2
ON1 - OSPF NSSA ext 1, ON2 - OSPF NSSA ext 2, a - Application
C 1::/64 [0/0]
via GigabitEthernet0/0/1, directly connected
L 1::1/128 [0/0]
via GigabitEthernet0/0/1, receive
OE2 1:1::/64 [110/10]
via FE80::CE7F:76FF:FE6A:B5E0, GigabitEthernet0/0/1
OE2 1:2::/64 [110/10]
via FE80::CE7F:76FF:FE6A:B5E0, GigabitEthernet0/0/1
OE2 1:3::/64 [110/10]
via FE80::CE7F:76FF:FE6A:B5E0, GigabitEthernet0/0/1
C 1:20::/64 [0/0]
via GigabitEthernet0/0/0, directly connected
L 1:20::1/128 [0/0]
via GigabitEthernet0/0/0, receive
OE2 1:30::/64 [110/10]
via FE80::CE7F:76FF:FE6A:B5E0, GigabitEthernet0/0/1
O 2::/64 [110/2]
via FE80::CE7F:76FF:FE6A:B5E0, GigabitEthernet0/0/1
OE2 2:1::/64 [110/10]
via FE80::CE7F:76FF:FE6A:B5E0, GigabitEthernet0/0/1
OE2 100:3::3/128 [110/10]
via FE80::CE7F:76FF:FE6A:B5E0, GigabitEthernet0/0/1
OE2 100:4::4/128 [110/10]
via FE80::CE7F:76FF:FE6A:B5E0, GigabitEthernet0/0/1
L FF00::/8 [0/0]
via Null0, receive
MIT License
Copyright (c) 2026 101zh
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.