THINKPeering
A GuidePurpose of This Guide
To demonstrate the features andbenefits of Peering as a resource,and how it helps businesses
connect faster, operate more
efficiently and lower costs.

Contents

What is Peering?
Reasons to Peer
Peering Types
Route Servers
Requirements for Peering
Tips for Positive Peering
Telehouse Peering Exchanges

What is Peering?
Peering is simply the settlement-freeexchange of Internet traffic.
Two separate networks voluntarily interconnect for the purpose of exchanging traffic
between the users of each network, without
paying a third party to carry that traffic overthe Internet for them.
Neither party pays the other in association
with the exchange of traffic. Each derives
revenue from its own customers.

Our goal as a Data Center provider is to ensure that
our customers utilize their resources most efficiently.

Reasons to Peer
Three main reasons why companies Peer:
To Save Money
Since the only thing you
actually pay for in a public
IP peering switch is theleased port, technically,
settlement charges don’t
exist. Your bandwidth isbasically FREE.
In essence, you’reaveraging down yourbandwidth costs.

It’s More Efficient
Tier 1 Internet Service
Providers typically route
your traffic throughround-about transit.
Peering keeps traffic local
by identifying the fastest
and most direct route.
This makes for fasterconnectivity and lower
costs.

Lower Latency
Network latency is anexpression of how muchtime it takes for a packetof data to get from one
designated point to another.
In some environments,
latency is measured bysending a packet that isreturned to the sender;
the round-trip time isconsidered the latency.

Transit costs more money...
Peering offers the fastest connection, which reduces cost.

Traffic Models: Transit vs. Peering
Transit:
Destination ISP ismultiple ISPs away.

Tier 1
Routing
TRSAN

ISP A

IT

ISP B

Source ISP
(You)
PEER

IN

ISP C

G

Destination
ISPPeering:
Destination ISP is close.

ISP D

Peering Types
The Three Types of Peering:

1. Symmetrical

2. Asymmetrical

3. No Customer

Symmetrical and Asymmetrical Peering
Symmetrical
The exchange of traffic between thetwo ISPs is about the same amount ineither direction. Both organizations
have a similar profile.

Tier 2
Provider A

Tier 2
Provider B

Same amount of traffic in both directions.

AsymmetricalTwo traffic-laden providers exchange
traffic, but one delivers more than theother. Both entities significantly reducetransit costs by peering each other.

Tier 2Provider A

Tier 2Provider B

Large traffic amount in one direction.

Peering is always evolving as provider needs change and grow.

Other Peering Models
Bilateral Peering (One-to-one)

Multilateral Peering (One-to-many)

ISP

ISP

ISP

ISP A

ISP B

ISP

1 ISP

ISP

ISP

(via RouteServers)

ISP

ISP
ISP

• Configure peering per peer
• Selective peering based on a policy• Typically for mid to large providers

ISP• Single peering configuration enables
peering with multiple peers• Open peering• Typically for contents providers

Other Peering Models
Bi-Directional(Between network-heavy ISPs)

ISP A

Uni-Directional(ISP delivers contents in one direction,to viewers)

ISP B

Exchange the same amount of traffic.

Exchange content-heavy to eyeball-heavy.

Public vs. Private Peering
Why Choose Public Over Private?
Most ISPs prefer public peering at
IXPs because it’s easier and more costeffective.
Private peering requires cabling, which
dramatically increases cost and time.
Public peering at an IXP costs lessbecause an ISP can Peer with multiple
ISPs with a single router interface.
In summary, Tier 2 providers need topeer on IXPs to maintain businessand stay competitive.
More About Peering Exchanges• Over 300 known global Internet
Exchange Points (IXPs)• Operated by both profit and non-profit
organizations• Carrier neutrality is key to successPrivate Peering• Peering directly via a cross connect• Need a cable per peering• Secure peering

Tier 2Provider

Tier 2Provider

Public Peering• Peering over an IXP• Need a single cable all peerings• Less secure than private peering

Tier 2
Provider

IXP

Tier 2
ProviderThe Two Types of IXPs in the Global Peering MarketLayer 2
The most widely used IXP is Layer 2. It’s
typically known as the Exchange Pointarchitecture. This type of IXP architecture iswell known in the US, Europe and in mostAsian markets.
Most IXPs select Layer 2 ethernet switches
as their platform for many reasons:• Proven platform for many years• Supports high speeds, 1G/10G/100G• Hardware cost is relatively cheap• Easy operation (no BGP operation)• Optional private peering via VLAN
Layer 3In this model participants are all connected
to a central router. This is something seenin countries like Korea or Australia where
all of their systems have to work together.
The participants all axis into one router.

Layer 2
Participant
RouterParticipant
RouterParticipant
RouterParticipant
RouterParticipant
RouterLayer 3
Participant
RouterParticipant
Router
IXP
RouterParticipant
RouterParticipant
RouterRoute Servers
NYIIX Route Servers (RS) (1)

NYIIX Route Servers (RS) (2)• For multilateral Peering• Has an outbound filter to distributeroutes• Must register your AS-SET in IRR• RS has an inbound filter to accept
only legitimate routes registered inAS-SET• The filter is updated daily• A Route Server works like aroute reflector. In this case, youmust register your AS-SET[AS-CUSTOMERS; AS-PEERS]
in IRR [Internet Routing Registry].
The RS is Route-Set• Has AS-SET AS-NYIIX, which is acombination of AS-SET of allparticipants• Participants can suppress specificroutes to RS. This is important.
If you have a customer who is alsoa Peer, you can suppress routing
to that customer through theexchange point.

Requirements for Peering
A connection to an exchange point:
You may need to install a router within the exchange point, or an Ethernet
circuit between your facility and theirs.
Traffic
You’ll need enough traffic to be worth
peering with, or have good Peeringarrangements.

A Peering Manger
They can determine which networks
you should be peering with, contact
those networks, and make arrangements.
A Peering Policy
Determine your own Peering Policies.

Positive Peering Tips
• Do NOT make a hard loop towards
IXP• Use only one MAC address• Secure your BGP session with MD5• Use BFD if possible (if peer agrees)• Check max-prefix limit• Never leak non-BGP protocols(e.g. OSPF, CDP) to IXP• Never set default-route to an IXPparticipant• Disable Proxy ARP (especiallyCisco)Telehouse Peering Exchanges
NYIIX

LAIIX

The New York International Internet
Exchange (NYIIX) is the largest in
the New York City Area. It wasestablished in 1996.

The Los Angeles International
Internet Exchange (LAIIX) wasestablished in 1998. It is a smaller
sibling and is part of a larger affiliation.

Colocation with TELEHOUSE is not a requirement to Peer with us.

For more information, please visit us at www.telehouse.com