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Failover using VRRP, OSPF & BFD
Federico Martín Perdichizzi
October 17th, 2016
Second Dubai MUM, Emirates
• Bachelor’s Degree in Organization’s Information Systems (In progress)
• MTCNA (1511NA064)
• MTCRE (1511RE099)
• MTCTCE (1511TCE030)
• MTCINE (1604INE052)
• 4 years working in networking with MikroTik
About me
2
• VRRP, OSPF & BFD: Description and properties
• Steps for configuration
• Testing failover
• Final comments
• Q & A
Outline
3
Original Network Topology
4
• Time to coordinate replacements
• Only 1 IP address allowed and unique gateway
• Building only accessible during working hours
• Second router with VRRP, OSPF & BFD
5
• Virtual Router Redundancy Protocol (RFC 3768)
• Virtual interface over physical
• Priorities (Master: 255, Backups: 1-254)
• Time of convergence
• IP address /32
VRRP
6
How does it work?
• Multicast packets
VRRP
• Same IP Addresses
VRID in Hex
• MAC Address 00-00-5E-00-01-XX
7
OSPF (Open Shortest Path First)• Internal Gateway Protocol
• Best path
Bidirectional Forwarding Detection• Session between two endpoints
• Hello packets each 200ms
• Wireless considerations
OSPF & BFD
8
Original Network Topology
9
Goal Network Topology
10
• Custom’s network has only 1 IP as GW for ours
• Non static ARP entries
• Wireless distance: Less than 400 meters
• No connection tracking used in redundant routers
Things to consider
11
Things to consider
Routes:Tunnels GW IP via VRRP
Routes:Customs subnets via VRRP
VRRP BACKUP
VRRP MASTER
Workout side Customs side
VRRP MASTER
VRRP BACKUP
NATNo connection tracking
12
• Best Practice
• Management
• Bridge -> Add
Loopback
13
Loopback
Lo IP= 10.255.255.1
Lo IP= 10.255.255.4Lo IP= 10.255.255.3
Lo IP= 10.255.255.2
14
Loopback
Lo IP= 10.255.255.1
Lo IP= 10.255.255.4Lo IP= 10.255.255.3
Lo IP= 10.255.255.2
• Static routes between all routers to reach Loopback IP’s (not physical mesh)
15
• How to
VRRP
16
VRRP
VRRP Master Interface VRRP Backup Interface17
• Assign Loopback IP to the default OSPF Instance on each router
OSPF
18
• Add network to start running the protocol
OSPF
19
• Make a customizable static interface
OSPF
20
• Adjust parameters
OSPF
21
• Default Setup• Check neighbors
BFD
22
Server Farms
Normal Packet Flow
OSPF Routes (Distance 110)
TLS link, principalWireless link, secondary
Master Router
Master Router
23
Server Farms
WKO TLS Router Fail
No route to host!
Master Router
Master Router
24
Server Farms
WKO TLS Router Fail
Static Routes (Distance 200)
Master Router
Master Router
25
Server Farms
TLS Failure
Master Router
Master Router
26
• Check Gateway: Ping
• Avoid manually add static routes
Why OSPF ?
27
• Very usefulEmail notification
VRRP Scripts
28
Thank you!
MUM Middle East, October 2016Federico Martín Perdichizzi
Any other question?
29