This presentation explains how to simplify networking by avoiding router limitations and multihoming with Juniper’s MX80. Read on to learn configurations and useful commands.

1. Multihoming using Juniper MX80
Howard Hart
CONFIDENTIAL

2. A short pause for a commercial
Rated #1
....
Break through Unique New
Voice Quality Voice Services
$
Free Phone Platform for Future
Service Managed Services

3. Ooma Business
• Hosted VoIP services used by hundreds of
thousands of customers
• Carrying over a hundred million minutes of
call traffic per month
• Pushing millions of packets per second
• Standards based VoIP using Session
Initiation Protocol (SIP) signaling and Real
Time Protocol (RTP) media

4. Ooma Challenges
• RTP is unforgiving and so are customers
– One dropped packet and user hears a pop
• Can buffer out-of-order RTP packets up to
100 msecs.
– Just five 20 msec packets for most codecs
• More than one network switch UNCLE
?
hasn’t been up to the challenge
at our scale

5. Why Juniper?
• We’ve got enough challenges--don’t need
to add router limitations to the mix
• MX80 provides wirespeed packet-
switching with zero buffering
– Average 40 msecs coast to coast
– Plus buffer bloat delays
– Plus local head-of-line blocking on NAT
• 50 million pps capacity on MX80 gives us
lots of headroom

6. Why multihome?
• Carriers go down
• Hardware fails
• Maybe some of your destinations are
cheaper through an alternate carrier
• Your resume’s a little light and you’re not
up to speed yet on Web 2.1

7. Topology
• Control inbound flow via BGP
announcements and AS prepending
• Control outbound flow via VRRP
• Automate failover using Juniper interface
tracking feature

8. Network Diagram
Interwebs Joesgarage Interwebs Joesgarage
ASN 1000 ASN 2000
2 6 6
2 172.16.1.4/30
172.16.1.0/30 10.1.1.0/30 10.1.1.4/30
5 5
xe-0/0/1 1 1
xe-0/0/2 xe-0/0/1 xe-0/0/2
xe-0/0/0 2 xe-0/0/0 3
Router 1 192.168.1.0/24 Router 2
ASN 12345

9. VRRP Configuration
Router1:
set interfaces xe-0/0/0 unit 0 family inet address 192.168.1.2/24 vrrp-group 0
edit interfaces xe-0/0/0 unit 0 family inet address 192.168.1.2/24 vrrp-group 0
set virtual-address 192.168.1.1;
set priority 100;
set track interface xe-0/0/1 priority-cost 10;
set track interface xe-0/0/2 priority-cost 5;
Router2:
set interfaces xe-0/0/0 unit 0 family inet address 192.168.1.3/24 vrrp-group 0
edit interfaces xe-0/0/0 unit 0 address 192.168.1.3/24 vrrp-group 0
set virtual-address 192.168.1.1;
set priority 120;
set track interface xe-0/0/1 priority-cost 25;
set track interface xe-0/0/2 priority-cost 10;

10. VRRP Configuration (cont)
• VRRP failover in 2 seconds or less – though
configurable with advertise-interval setting
• VRRP tracks local interfaces--can’t be easily tied
to BGP state
• Subtract priority-cost from priority when link
goes down
– Router2 xe-0/0/1 is the preferred outbound interface
at priority 120
– If Router2 xe-0/0/1 goes down, Router1 xe-0/0/1
takes over
• 120 – 25 = 95 < Router1 xe-0/0/1 priority 100

11. BGP Configuration
Router 1
[edit protocols bgp]
set local-as 12345;
set group interwebs type external;
set group interwebs export bgpnets;
set group interwebs neighbor 172.16.1.2 peer-as 1000;
set group joesgarage type external;
set group joesgarage import lowerpref;
set group joesgarage export [ prepend5X bgpnets ];
set group joesgarage neighbor 10.1.1.2 peer-as 2000;
[edit policy-options]
set policy-statement bgpnets term to-allow from protocol [ direct static ];
set policy-statement bgpnets term to-allow from route-filter 192.168.1.0/24 exact;
set policy-statement bgpnets term to-allow then accept;
set policy-statement lowerpref then local-preference 90;
set policy-statement prepend5X then as-path-prepend “12345 12345 12345 12345 12345”;

12. BGP Configuration (cont)
• Router with fewest prepends wins for inbound
traffic
• Use local preference (default 100) to steer traffic
out preferred outbound provider
• BGP failover after (typical) 30 second
reconvergence
• Prepending doesn’t protect from flapping
– Web users just hit reload. VoIP customers hit speed
dial to customer support
• Throw in BGP community usage to fine tune
specific carriers through specific interfaces

13. Useful Commands
• Show vrrp
Interface State Group VR state VR Mode Timer Type Address
xe-0/0/0.0 up 0 master Active D 3.453 lcl 192.168.1.2
• Show bgp summary
• Show route protocol bgp <network>
• Show bgp group
• Show nearest open bar

14. Questions?
2012