1. Overview
IX is called Internet eXchage, IXP Internet eXchange Point or NAP Network Access Point. IX means Internet internetworking network for seamless exchange of domestic Internet traffic, generated by domestic ISP (Internet Service Providers), without going through international hosts.

2. The role of IX
Today, explosive demand of Internet which allows exchange of various and enormous amount of information is expanding the need of network service worldwide as well as in Korea and the number of users keep increasing. This phenomenon basically leads to quantitative expansion of ISPs.

However, the inefficiency caused by lack of backbone network which can integrally afford these ISPs has been a real issue. If a user of a specific ISP wants to connect to other ISPs in Korea , he should go through international Internet service providers because of poor traffic internetworking among ISPs in Korea . This degraded the efficiency of traffic exchange and SMB ISPs should consider a separate and costly plan for internetworking with international networks.

As a comprehensive network system providing mutual connectivity among domestic ISPs, IX is implemented to secure the traffic efficiency among domestic ISP networks to relieve economical burden of individual ISP, and to prevent waste of national resources. Now the Internet traffic exchanged only in Korea doesn't have to go through international hosts and an environment in which data sending and receiving time is dramatically reduced is guaranteed because of IX

1. The history of domestic IX
Before domestic IX is emerged, KT launched Internet commercial service called KORNET in June 1994 for the first time and then Dacom, Inet, and Nowcom, etc. started the service thereafter. At that time, domestic ISP network size was not so huge that domestic and international Internet connection was implemented through international Transit service on top of each ISP's single backbone network.

Korea Computerization Agency started internetworking service for pubic networks including educational network and research network in 1995 and expanded the service to commercial ISPs to improve poor data exchange throughput resulted from domestic traffic going through international hosts because internetworking among domestic ISPs was not efficient and seamless. This is the beginning of IX in Korea.

	1995. 2 Internetworking for educational network and research network drove by KRNIC of Korea Computerization Agency
	1995. 8 Implemented Korea Computerization Agency KIX which is the first Internet exchange node in Korea (traffic exchange among domestic 8 ISPs)
	1995. 2 Internetworking among 14 ISPs including KT (Kornet), Dacom (Boranet), Nurinet, etc. based on KIX
	1996. 4 KT started domestic exchange service called EIX(Expo Internet eXchange)
	1996. 12 Transferred commercial network of KIX to private providers like KT and Dacom excluding non-commercial government public network IX(Korea Telecom Internet eXchange), DIX(Dacom Internet eXchange) emerged)
	1998. 8 Formed 'Korea Internet Internetworking Association' by domestic main ISPs and late starting ISPs excluding KT and Dacom
	1999. 6 Opened KINX (Korea Internet Neutral eXchange) internetworking center for traffic internetworking among membership companies of Korea Internet Internetworking Association.
	2000. 6 Founded KINX for efficient operation of internetworking center (co-investment by 13 ISPs)
	2001. 10 Opened the first IPv6 IX called 6NGIX in Korea (Korea Computerization Agency)
	2002. 2 Formed Korea Internet eX change Association to promote the development of domestic IX (KIX, KT-IX, DIX, KINX, etc. involved)
	2003. 5 Implemented the first regional IX called BIX (Busan Internet eXchange) (Korea Computerization Agency)

2. Domestic IX Implementation

	At the early stage of Internet, KRNIC (NIDA now), an internal organization of Korea Computerization Agency, drove internetworking among educational network and research network, etc. to prevent domestic Internet traffic from unnecessary routing through international hosts. This is the beginning of IX in Korea .
	There are currently 5 domestic main IXs: KIX which started the first IX service in 1995, KT-IX emerged in 1996 based on EIX(Expo Internet eXchange), DIX which started the service since it took over commercial network from KIX in 1996, KINX which started the service in 1999 based on Korea Internet Internetworking Association which is an association of small and medium level ISPs, and BIX which is created for seamless traffic flow in Busan-Gyungnam area in 2003.
	KIX(Korea Internet eXchange) and BIX(Busan Internet eXchange) is being operated by Korea Computerization Agency on a non-commercial basis and KT-IX(Korea Telecom Internet eXchange) and DIX(Dacom Internet eXchange) is being operated by infrastructure communication providers, that is, KT and Dacom on a profit basis and KINX(Korea Internet Neutral eXchange) is initially created by non-commercial organization, that is, Korea Internet Internetworking Association but now it is being operated by KINX co-founded by 11 membership ISPs of the association.
	BIX is the first regional Internet exchanage node (R-IX) implemented as a part of broadband national network project drove by the government to improve national Internet internetworking structure which was Seoul-oriented and to eliminate information utilization difference among regions.
	Among these IXs, KIX (www.kix.ne.kr) and BIX (www.busanix.net) are providing information about public network IX through a dedicated homepage of Korea Computerization Agency as well as services including Looking Glass, Traceroute, Whoislookup, etc. in both Korean and English.
	Among commercial IXs, KT-IX and DIX don't have their dedicated homepages even though KIX provided IX information through www.kix.net before, but not now. DIX is classified into one of service products at dedicated line product homepage of Dacom (www.bora.net) with some information about IX.
	KINX (www.kinx.net) is providing information about its IX through English and Korean homepages and is providing differentiated service with separate login process for each customer.

[Table 1] The features of domestic IX

2) Connection Status

	KIX is mutually connected to 5 commercial Internet networks including KT, Dacom, KINX, etc. for mutual internetworking and efficient traffic exchange among non-commercial public network such as PUBNet, KOREN, KREONet, and 6NGIX. Currently 9 public and commercial ISPs are mutually connected at total 47.5Gbps bandwidth.
	As a national important infrastructure, the connection point is located at the 15th floor of Korea Computerization Agency (Mookyo-dong Joong-gu Seoul ).

[Table 2] Internetworking status per domestic IX

※ Source: Korea Internet White Paper (2005)

	BIX is composed of 4 non-commercial public networks in Busan-Gyungnam area including Korea Science and Technology Information Institute, Busan Educational Inforamtion Institute, PUBnet, and PUBNet PLUS and 4 more commercial ISPs such as KT, Dacom, and Onse communication, etc. and they are connected at total 8.6Gbps bandwidth.
	The connection point is located at the 1st floor of Busan Educational Information Institute.

	KT-IX is currently the most biggest traffic exchange node in Korea and total 33 ISPs are connected at 242Gbps bandwidth. It is separated into Hyewha node and Guro node to effectively counteract nationwide disasters or troubles.
	As a national important infrastructure, the connection points are located at both KT Hyewha branch (Yeongeon-dong Jongro-gu Seoul) and Guro branch (Guro-dong Guro-gu)

	DIX is remodeled by integrating KIDC) backbone network and Dacom IX backbone network at Seocho center to provide improved connection service to IX subscribers for KIDC which is the biggest Internet data center. Currently, approx. 40 ISPs are connected at 167Gbps bandwidth.
	As a national important infrastructure, the connection point is located at KIDC center (Nonhyun-dong Seocho-gu Seoul ).

	KINX is an IX specialty company, not a line provider. 35 subscribers are mutually connected at total 88.6Gbps bandwidth through Peering connection. A separate Transit connection between subscribers is allowed for each customer at IX center.
	As a national important infrastructure, the connection point is located at the 5th floor of Daerim Acrotel (Dogok-dong Gangnam-gu Seoul ).

	There are two types of domestic IX connections: Layer2 (L2) based on switch equipment and Layer3 (L3) based on router equipment.
	Only KINX is uniquely using L2 connection type. Although DIX provided L2 connection type service in its early stage, it's now using L3 type. KIX also has provided L2 connection type for some subscribers, but there is no subscriber who want to use L2.
	L3 connects dedicated lines from POP of subscribers to router port directly without going through a separate network equipment by installing backbone router equipment at IX center. It basically supports WAN type such as DS-3(45Mbps), OC-3(155Mbps), OC-12(622Mbps), and OC-48(2.5Gbps) and it now supports GibabitEthernet(1Gbps) and 10GigabitEthernet(10Gbps) type. KIX, BIX, KT-IX, and DIX are using L3 connection type
	KINX provides L3 connection by using Route Server. Route Server with L3 connection gets routing information by peering from backbone switch and it transfers the information to other subscribers. Even thought it's supporting L3 connection type, it should be considered as an added service of IX which usually uses L2 connection.

3. Analysis of policy features

	KIX connection criteria are listed in a separate web document
	According to the criteria, public Internet network including non-commercial ISPs, public organizations, non-commercial organizations and commercial IX networks can access KIX. Others need an approval from the director of Korea Computerization Agency.
	Each subscriber can choose and install a dedicated line in WAN which is required for KIX connection by himself.

	BIX is also posting connection criteria on the web just as KIX.
	The connection to BIX is limited to ISPs in Busan-Gyungnam area and any negotiated parties. This is because the objective of this IX is to contribute to solve information utilization difference among regions caused by Internet quality by promoting effective use of national communication resources and improvement of Internet quality of Busan-Gyungnam area by enabling the regional IX to process Internet traffic of Busan-Gyungnam area without going through Seoul IX.
	Each subscriber can choose and install a dedicated line in WAN which is required for BIX connection by himself.

	KT-IX and DIX didn't disclose any official connection criteria yet, but we can say their criteria are very close to the previously mentioned connection criteria when reviewing IX related official meeting. We can understand their situation when we consider KT and Dacom are monstrous line communication providers in Korea competing with each other with very similar service products.
	The basic connection criteria of KT-IX is based on domestic ISPs registered in NIDA, and it basically assumes duplicate configuration for network safety, that is, Multi-homed Network configuration and the dedicated line, which is provided by a communication provider who operates corresponding IX.
	Both General BGP subscribers who have BGP AS number and System Operator (SO) are allowed to connect KORNET network, rather than KT-IX network.
	The connection speed shall be DS-3 (45Mbps) or higher.

	The basic connection criteria of DIX is also based on domestic ISPs registered in NIDA just as KT-IX, and it also basically assumes duplicate configuration for network safety, that is, Multi-homed Network configuration and the dedicated line, which is provided by a communication provider who operates corresponding IX.
	However, it allows DIX connection to SO, not like KT-IX.
	The connection speed shall be DS-3 (45Mbps) or higher.

	The connection criteria of KINX are recently changed from its early stage criteria.
	The connection is allowed only for ISPs who have membership with 'Internet Internetworking Association', but any domestic or international organization or business can access KINX if they have BGP AS number.
	However, the network equipment of corresponding company shall be installed in KINX IX center for KINX connection, and the router shall be basically equipped with a port supporting Ethernet framing. Switch or other equipments may be able to be installed in discussion with IX administrator.
	However, 1000Base-LX/LH shall be observed when the connection is 10GigabitEthernet and installation of additional network equipment is optional for this case.
	A subscriber can choose a dedicated line configuration outside of IX center.

	It allows unlimited connection among ISPs and organizations by guaranteeing interoperability between commercial networks and public Internet networks and provides domestic full routing information to commercial networks. However, there is no internetworking among commercial networks which go through KIX.
	The routing information obtained from internetworking among commercial networks is provided only to public Internet networks, not to other commercial networks.
	However, limited internetworking is allowed when a trouble or emergency occurs, so it can play a critical role in exchanging Internet traffic among commercial networks in Internet emergency.
	However, the bandwidths of commercial networks connected to KIX are KIX-KTIX(2Gbps), KIX-DIX(2Gbps), and KIX-KINX(11Gbps), etc. When we consider the traffic capability of each IX is min. 22Gbps to max. 100Gbps, we can't expect KIX to play a critical role in the event of nationwide Internet emergency.

	Basically, this is for mutual exchange of all routing information related to Internet traffic in Busan-Gyungnam area.
	BIX delivers all routing information of Internet traffic in Busan-Gyungnam area and IX and internetworking organization in Busan area can limit the delivery of traffic and routing information not complying with the objectives of IX implementation.

	Based on the port of IX backbone equipment, there are two different routing policy, that is, Inbound Routing Policy and Outbound Routing Policy.
	Inbound Routing Policy is the routing information received from IX subscribers and it has the routing information (IX subscriber's BGP AS ) of IX subscriber's IP network and IX subscriber's customer's BGP AS.
	Outbound Routing Policy is the routing information delivering received routing information from IX subscribers to each IX subscriber and it has BGP AS information of all the IX subscribers.
	KT-IX delivers full routing information of all IX subscribers for outbound routing policy, but it allows limited routing information for inbound routing information.
	The limited scope of inbound routing information is changing in accordance with market environment change, and it basically allows BGP AS information of corresponding IX subscribers and customer's BGP AS information just for non-commercial purpose. Of course, the limitation criteria are also different for the contract conditions of each subscriber.

It has the same routing policy as KT-IX.

	IX subscribers have all the authorities for routing policy of KINX which is operated based on Layer2 connection.
	However, KINX recommends the followings to subscribers for routing policy. a. For the network equipment of IX membership company, outbound routing information shall include its own routing information of each company and all the customers' BGP AS information. b. For the network equipment of IX membership company, inbound routing information shall apply No filter to all the traffic of membership companies only excluding any possible troublesome traffic. c. Routing information delivered to each membership company shall include only IPs assigned by international certification organizations such as InterNIC, RIPE-NCC, APNIC, KRNIC and corresponding subsidiary organizations. d. When exchanging BGP information of each membership company, the default routing information (0.0.0.0) shall not be delivered.
	KINX doesn't force attending customers to enable mutual full peering for all the membership companies, but they need to do full peering at least for 20% of total membership companies.

[Table 3] The features of domestic IX policy