Redundant Internet service provision - customer viewpoint
1. Redundant Internet service provision -
customer viewpoint
Kae Hsu
kae@du.net.tw
Communication Network Dept.
2. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
2 2006/09/07
3. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
3 2006/09/07
4. Requirement of redundant
http://www.seed.net.tw
Internet access is a very important service
today for:
Enterprise/business
Tools of operation
Decreasing the cost
Increasing the revenue
Consumers
Communication tools
Entertainment
Customers need redundant service provision
4 2006/09/07
5. Requirement of redundant
http://www.seed.net.tw
It was expensive to build a redundant
Internet topology for end-user before:
Use leased line/ISDN for backup only
Less circuit utilization
Expensive network equipments
Complex network operation
5 2006/09/07
6. Requirement of redundant
http://www.seed.net.tw
Today, new type of circuit provides simple
and convenient way to build a redundant
Internet access service
FTTx
xDSL
Wireless
More and more cheap and efficient network
equipments appear
SP could provide enough redundant service
for customer requirements
6 2006/09/07
7. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
7 2006/09/07
8. Types of redundant
http://www.seed.net.tw
3 types of redundant (1)
Backup
Redundant circuit
Primary: expensive, better quality
Backup: cheap, less bandwidth
Use backup circuit only when primary circuit is
failure
8 2006/09/07
9. Types of redundant - Backup
http://www.seed.net.tw
Traditional circuit backup topology
Leased Line
PE
ISP
CE
ISDN
PE User
ISP
PE X
Leased Line
CE
ISDN
PE User
Customers need cheaper and higher
bandwidth backup solution
9 2006/09/07
10. Types of redundant - Backup
http://www.seed.net.tw
New circuit backup topology
Leased Line
PE
ISP
CE
xDSL
User
BRAS
Leased Line
PE
ISP
CE
FTTx
User
BRAS
FTTx
PE
ISP
CE
xDSL
10 2006/09/07 User
BRAS
11. Types of redundant - Backup
http://www.seed.net.tw
New circuit backup topology
xDSL
ISP BRAS
CE
PE wireless User
When customers use two permanent circuits,
they hope to use these two circuits at the
same time
11 2006/09/07
12. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
12 2006/09/07
13. Types of redundant
http://www.seed.net.tw
3 types of redundant (2)
Load-sharing
Redundant circuit
Usually use the same type of circuit
Sometimes two circuits with the different type
but the same bandwidth is possible
Sharing traffic among those circuits
Redundant PE/CE (option)
Prevent any single-point failure
13 2006/09/07
14. Types of redundant – Load-sharing
http://www.seed.net.tw
Basic topology of load-sharing
Leased line
ISP
PE CE
Leased line
User
ISP
PE
X
Leased line
CE
Leased line
User
14 2006/09/07
15. Types of redundant – Load-sharing
http://www.seed.net.tw
Advanced topology of load-sharing
Leased line
PE CE
ISP
PE Leased line CE
User
Some customers think to connect to only one
SP is risky
They need redundant option on SP issue
15 2006/09/07
16. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
16 2006/09/07
17. Types of redundant
http://www.seed.net.tw
3 types of redundant (3)
Multihoming
Redundant circuit
Usually use the same type of circuit
Sometimes two circuits with the different type
but the same bandwidth is possible
Sharing traffic between those circuits
Redundant CE (option)
Prevent single-point failure on CE router
Redundant service provider
Prevent single-point failure on SP
17 2006/09/07
18. Types of redundant - Multihoming
http://www.seed.net.tw
Lots of documents talks about BGP
multihoming
Only discuss REAL cases that our customer
ask us to provision here
Our customer uses the IP block(s) from RIR
(TWNIC) only
seednet did not provide IP blocks for
multihoming service
18 2006/09/07
19. Types of redundant - Multihoming
http://www.seed.net.tw
Three ways to provision multihoming service
Customers use BGP to exchange routing
information between SP with their AS# from
RIR
Customers use BGP to exchange routing
information between SP with private AS#
Customers do not use BGP to exchange routing
information between SP
19 2006/09/07
20. Types of redundant - Multihoming
http://www.seed.net.tw
Customers use BGP to exchange routing
information between SP with their AS# from
RIR
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SP announce full Internet routes or default
route only to customer
20 2006/09/07
21. Types of redundant - Multihoming
http://www.seed.net.tw
Discussion for customers use BGP to exchange
routing information between SP with their
AS# from RIR:
Customers have to apply AS# from RIR
It is no necessary if those customers use their
BGP network for redundant Internet access
only (e.g. NOT for transit)
Customers have to maintain BGP by themselves
Not so much engineers in customer site know
well and have no fear on BGP
Any more suitable solution?
21 2006/09/07
22. Types of redundant - Multihoming
http://www.seed.net.tw
Customers use BGP to exchange routing
information between SP with private AS#
0
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Internet 172.20.0.0/20
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SP announce full Internet routes or default
route to customer
22 2006/09/07
23. Types of redundant - Multihoming
http://www.seed.net.tw
Customers use BGP to exchange routing
information between SP with private AS#
Customer have to maintain BGP by themselves
Not so much engineers in customer site know
well and have no fear on BGP
Obviously, the ability for BGP is the key
Any solution to remove BGP here?
23 2006/09/07
24. Types of redundant - Multihoming
http://www.seed.net.tw
Customers do NOT use BGP to exchange
routing information between SP
export IGP
0 0 172.20.0.0/21
10 0/2
e AS 20.0. 172.20.8.0/21
ounc , 172.
ann .0/21 ISP1 AS100
.0
2 .20
17
Internet 172.20.0.0/20
User
17
2.2 ann
0.8 oun
.0/ ce ISP2 AS200
21
, 1 AS2
72 00 export IGP
.20
.0. 172.20.0.0/21
0/2
0 172.20.8.0/21
SP does not announce any route to customer
24 2006/09/07
25. Types of redundant - Multihoming
http://www.seed.net.tw
Customers do not use BGP to exchange routing
information between SP
Customer have to maintain their output traffic
by some ways
Flow based load-sharing
» Use equal cost default route only
» Asymmetric routing status happened
Policy-based routing (Cisco)
» Keep the symmetric routing status
» Use “PBR Recursive Next Hop” to increase the
reliability
Filter-based forwarding (Juniper)
» Keep the symmetric routing status
» Use multiple routing table to increase the
reliability
25 2006/09/07
26. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
26 2006/09/07
27. Challenge to service provider
http://www.seed.net.tw
To provide the new topology for backup and
load-sharing redundant, SP needs new
equipments and routing architecture too.
New equipments for new circuit
New routing architecture
Ways to control customer routes in SP
backbone
27 2006/09/07
28. Challenge to service provider
http://www.seed.net.tw
In the old backup topology, backup route
would not appear in backbone
export IGP Leased Line
PE
ISP
CE
ISDN
PE User
When the primary circuit fail, the ISDN
dial-up and change the routing status
X
export IGP
PE X
Leased Line
ISP
CE
export IGP ISDN
PE User
28 2006/09/07
29. Challenge to service provider
http://www.seed.net.tw
In the new backup topology, customers use
permanent circuit for backup
Backup route leaks in the network
Need to differentiate the primary/backup
routes in the backbone network
export iBGP, high
local-preference Leased Line
PE
ISP
CE
export iBGP, low xDSL
local-preference User
BRAS
Have to re-configure backbone routing
topology if the old one is not suitable now
29 2006/09/07
30. Challenge to service provider
http://www.seed.net.tw
In the redundant load-sharing topology,
suitable routing architecture is necessary
too
export iBGP
192.168.100.0/25 high
192.168.100.128/25 low
FTTx
PE
ISP
192.168.100.0/24
xDSL CE
BRAS User
export iBGP
192.168.100.0/25 low
192.168.100.128/25 high
Customers have to maintain default route by
themselves
30 2006/09/07
31. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
31 2006/09/07
32. Solution for consumers
http://www.seed.net.tw
Basically, only enterprises will use those
redundant solution above
Sometimes consumers/SOHO would use
Internet access for crucial purpose:
Health and Medical Care
Small business
Any solution for consumers/SOHO to own
their reliable Internet access?
32 2006/09/07
33. Solution for consumers
http://www.seed.net.tw
There are many “multihoming gateway”
network equipment
The function of those equipment include:
Load balance capacity
Security
VPN
QoS
Common service
Basic routing
Reliability
..........
33 2006/09/07
34. Solution for consumers
http://www.seed.net.tw
Consumers/SOHO could buy those equipment
and use them for redundant Internet access
This kind of redundant does NOT need the
help from SP ATU-R
ISP1 Multihoming
gateway
ATU-R
consumer
Internet ISP2 network
ATU-R
Multihoming
ISP3 gateway
ATU-R
SP has to increase the quality to keep the
customers
34 2006/09/07
35. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
35 2006/09/07
36. Another redundant issue – MPLS VPN
http://www.seed.net.tw
If customers only want to use backup or
load-sharing solution, they could use the
architectures above
But to use multihoming solution is difficult,
Inter-AS MPLS VPN is not widespread like
Internet access
Mostly customers use MPLS VPN for crucial
service
How can we propose suitable solution for
MPLS VPN redundant?
36 2006/09/07
37. Another redundant issue – MPLS VPN
http://www.seed.net.tw
Build redundant network on Internet
For security reason, IPsec is required
Leased
Line CE
xDSL
PE IPsec
Tunnel BRAS
seednet
Internet
MPLS core
PE
BRAS
Leased xDSL
Line
CE
37 2006/09/07
38. Another redundant issue – MPLS VPN
http://www.seed.net.tw
Build redundant network on different SP
network
Leased
Line CE
xDSL
PE
BRAS
seednet ATM
MPLS core ATM core trunk
PE
BRAS
PE
BRAS
Leased xDSL
Line
CE
38 2006/09/07
39. Another redundant issue – MPLS VPN
http://www.seed.net.tw
Build redundant network on 3G network
Leased
Line CE
PE IPsec
Tunnel
seednet
MPLS core 3Gcore
PE
Leased
Line
CE
39 2006/09/07
40. Agenda
http://www.seed.net.tw
Requirement of redundant
Types of redundant
Backup
Load-sharing
Multihoming
Challenge to service provider
Solution for consumers
Another redundant issue – MPLS VPN
Next challenge
40 2006/09/07
41. Next challenge
http://www.seed.net.tw
More redundant circuit type in future?
More redundant service provision?
BGP anycast
Next challenge to service provider??
41 2006/09/07