Common requirements for all ISPs

Transcription

1 Introduc)on

2 Introduc)on In the transi)on state from IPv4 to IPv6, we should consider We cannot assign new global IPv4 addresses for new subscribers The network (par)cularly access NW) may have only IPv4 capabili)es or only IPv6 capabili)es There are many deployment solu)ons for such cases IPv6 over IPv4, IPv4 over IPv6 and Protocol Transla)on, etc., Requirements of each network provider are different depending on various factors, so appropriate solu)ons are also different For exis)ng user or new user? For exis)ng infrastructure or newly deployed infrastructure? For IPv4 only network or IPv6 only network? This presenta)on shows our case study for the transi)on at Yahoo! Broadband (Y!BB) which 2 is one of largest ISPs in Japan

3 Common requirements for all ISPs We should provide both of IPv4 and IPv6 connec)vity No more IPv4 global address in near future No addi)onal ARPU by IPv6 nor sharing global IPv4 address, so addi)onal CAPEX and OPEX should be minimized Keeping a record of IP address assignment (and port assignment if NAPT will be used) is mandatory and should have good scalability 3

4 Overview of Japanese ISP industry Application services (Mail / Web / Contents) Domestic backbone and connectivity to the Internet NW inter prefectures NW in each prefecture Leasing DF and CO sites from NTT East/West This boundary is depend on the size of each ISP and the size of each prefecture Access (DF / Metal) 4

5 Current situa)on of Y!BB Y!BB has two different types of access network 1. ADSL access network 2. FTTH access network ADSL access network Pure IP- based access network (not PPPoE based) We built L3 network by ourselves, leasing L1 or L2 circuits from NTT and other carriers # of subscribers is slightly decreasing FTTH access network NTT East and West built L3 access network, we are leasing L2 connec)vity from them # of subscribers is increasing 5

6 ADSL access network vs. FTTH access network NTT s CO-site Our Router NTT s Router Y!BB s Nationwide backbone ADSL Access network DSLAM CPE FTTH Access network PON CPE 6

7 Y!BB case study for ADSL access network 7

8 Condi)ons and requirements in Y!BB ADSL access network Exis)ng subscribers already have IPv4 global addresses and the # of subscribers is slightly decreasing We don t need to consider how to provide IPv4 connec)vity Just using IPv4 global address is enough ADSL access network is IPv4 only network Replacing or upgrading all devices to enable IPv6 is not realis)c We will need 6 over 4 technology to provide IPv6 connec)vity Since we are providing ADSL modems as CPEs, we can control so`ware in CPEs On the other hand, we want to minimize configura)on cost of CPEs 8

9 Our decision - 6RD - L3 (IPv4) 6rd CPE 6rd Relay Router 6rd CPE IPv4 address is used as internal ID IPv6 prefix which is delegated for each subscriber is derived from global IPv4 address which is assigned for same subscriber CPE can automa)cally configure its delegated IPv6 prefix to home network For downstream packet, 6rd relay router can automa)cally form encap header from dst IPv6 address of incoming packet (without configuring a tunnel for each subs) For upstream packet, CPE can figure out tunnel end point (6rd relay router or other CPE) from dst IPv6 address 6rd Domain 9

10 6rd behavior Prefix Delega)on IPv6 (*)6rd Prefix =2001:db8::/32 6rd Relay Router 2001:db8::1 tun0 address tun0 =2001:db8:a01:101::1/32 (*) LAN IPv4 address and RA are automatically genarated from WAN IPv4 address and 6rd prefix CPE 6rd Router IPv4 LAN address=2001:db8:a02:202::1/64 10 (*) tun0 address =Unnumbered rd Relay = tun RA=2001:db8:a02:202::/64

11 6rd behavior : Packet transfer (Downstream) IPv6 routing table 2001:db8::/32 => tun0 Default => 2001:db8::2 6rd Relay Router IPv6 tun0 Packet 2001:db8:: IPv6 IPv6 routing table :db8::/32 => 2001:db8::1 (*)6RD Prefix=2400:2db8::/32... Dst=2001:db8:a02:202:x:x:x:x Src=IPv6 Src address tun0=2001:db8:a01:101::1/32 (*) IPv6 routing table Packet IPv6 IPv4 IPv4 Dst= Src= Dst=2001:db8:a02:202:x:x:x:x Src=IPv6 src address Default => tun0 CPE 6rd Router tun LAN address=2001:db8:a02:202::1/64 11 (*) tun0=unnumbered Packet IPv6 6to4 Relay = RA=2001:db8:a02:202::/64

12 6rd behavior : Packet transfer (Upstream to external) IPv6 routing table 2001:db8::/32 => tun0 Default => 2001:db8::2 6rd Relay Router IPv6 Packet 2001:db8::1 tun0=2001:db8:a01:101::1/32 (*) tun IPv6 routing table :db8::/32 => 2001:db8::1 (*)6RD Prefix=2001:db8::/32... IPv6 IPv6 routing table IPv4 Packet IPv6 IPv4 Dst= Src= Dst=IPv6 dst address Src=2001:db8:a02:202:x:x:x:x Default => tun0 CPE 6rd Router tun LAN address=2001:db8:a02:202::1/64 12 (*) tun0=unnumbered Packet IPv6 6to4 Relay = RA=2001:db8:a02:202::/64

13 6rd behavior : Packet transfer (Upstream to internal) IPv6 routing table 2001:db8::/32 => tun0 Default => 2001:db8::2 6rd Relay Router IPv6 (*)6RD IPv6 Prefix=2400:2db8::/32 routing table :db8::/32 => 2001:db8:: :db8::1 tun0=2001:db8:a01:101::1/32 (*) tun Packet IPv6 IPv4 Dst=A.B.C.D Src= IPv6 routing table Default => tun0 CPE 6rd Router IPv4 tun LAN address=2001:db8:a02:202::1/64 13 (*) tun0=unnumbered Packet 6to4 Relay = Dst=2001:db8:AB:CD:x:x:x:x Src=2001:db8:a02:202:x:x:x:x IPv RA=2001:db8:a02:202::/64

14 Why we choose 6RD? - Cost Comparison - Each customer needs tunnel state/config Single tunnel aggregates all customers 6over4 L2TP IPSec 14

15 Facili)es cost simula)on with modeling method Server Can work as tunnel concentrator and 6rd relay server Uplink 1Gbps 15,000 Session JPY1,500,000 USD16,667 Aggrega)on Router Uplink 10Gbps Max Aggrega)on 10 servers (N+1 Redundancy) JPY3,000,000 USD33,333 Per customer IPv6 traffic 2.3kbps 15

16 How many customers can a server have? - 6rd - Aggrega8on Router 10G 10G 1G 1G 6rd relay server Redundant server (N+1) Need the server when 430,000 customers increase 16

17 How many customers can a server have? - Other solu)ons - Aggrega8on Router 10G 10G 1G 1G Tunnel Concentrator Redundant server (N+1) Need the server when 15,000 customers increase 17

18 How much does it cost to provide IPv6 service for One million customers? 6rd Other solu)on # of server 4 74 # of aggrega)on router cost 2 14 JPY1,200 USD133,333 JPY15,200 USD1,688,888 Cost Effec)ve! 18

19 Y!BB case study for FTTH access network 19

20 Background NTT East and West assign their own IPv6 address for each user, but this address is not for the internet connec)vity # of customer is increasing We need to provide both of IPv4 and IPv6 service over NTT s network We should share a IPv4 global address between mul)ple customers Big Ques)on How to provide OUR IPv6 service over other SP s IPv6 network? How to share one IPv4 address with many customers? 20

21 21 Two candidates for IPv6 connec)vity

22 4RD Candidate solu)ons for IPv4 connec)vity We need to provide IPv4 connec)vity over IPv6 network, sharing a global IPv4 address between mul)ple subscribers Possible solu)ons are; DS- Lite + LSN with dynamic port assignment DS- Lite + LSN with fixed port assignment DS- Lite + A+P Etc. What s cri)cal point for us? Scalability for keeping a record of IP address assignment and port number assignment 22

23 4RD LSN or A+P All of them use L4 port number as a part of host iden)fier, in addi)on to IP address Major technical differences are; Port assignment aspect LSN with dynamic port assignment assigns unique L4 port number for each session whenever new session is ini)ated A+P and LSN with fixed port assignment assign unique range of L4 port numbers for each subscriber when a IP address is assigned to Loca)on of address and port transla)on Center side in LSN CPE side in A+P 23

24 4RD Common issues for address sharing Common issues for address sharing techniques Src port number should be logged to access log on server side in addi)on to src IP address (for abuse etc.) Max number of concurrent session for each user is limited Since randomness of port number is restricted, it may have some impacts for security Some protocols, which contain L4 port number in its payload, may be impacted and ALGs are required However, NAPT also has same issue, and we already overcame it. Above issues should be overcame since it is common for address sharing solu)ons, and we believe we can do it Remaining and hardest issue is scalability of LSN itself 24

25 4RD Scalability of LSN with dynamic port assignment Session table which LSN box with dynamic port assignment should maintain (Size per session)= Private src address (32bit) + Private src port (16bit) +Global src address (32bit) + Global src port (16bit) = 12Byte (Table size per million users) = (Size per session) * (Max # of concurrent session per million users) = 12Byte * 19M sessions = 228MByte Session log which LSN box with dynamic port assignment should store (Size per session) = Private src address (32bit) + Private src port (16bit) +Global src address (32bit) + Global src port (16bit) + Timestamp (64bit) = 20Byte (Monthly log size per million users) = (Size per session) * (Total # of sessions per million users in one day) * 180days = 20Byte * 8.6G sessions/day * 180days = 30.96TB/6month Even though it seems these impacts are acceptable, we still want to minimize cost since there is no additional ARPU. 25

26 4RD Summary To provide IPv6 connec)vity for our ADSL access network We will use 6rd since it is cost effec)ve, scalable, and minimum CPE configura)ons To provide IPv6 connec)vity for our FTTH access network We will use Plan- 4 since it is more scalable for number of subscribers and doesn t require NAPT for IPv6 (Please re- think more clear name > Ichiro) To provide IPv4 connec)vity for our FTTH access network Even though cost effec)veness and scalability of LSN is acceptable, we are s)ll inves)ga)ng beuer solu)on including A+P 26