Internet Engineering Task Force Q. Ma Internet-Draft L. Li Intended status: Informational T. Yang Expires: January 17, 2013 China Mobile July 16, 2012 Terminal Test of IPv6 support and DNS Query draft-ma-v6ops-terminal-test-01 Abstract This document introduces the terminal test under the WLAN environment .The test includes the ability for terminal to obtain IPv6 address, the sequence of DNS records query and termina behaviors in the condition of DNS records abnormal, for example DNS records are incorrect or absent. Several personal computers and smart phones with different operational system have been tested. The test results have been discussed and to share with internet community. Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on January 17, 2013. Copyright Notice Copyright (c) 2012 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must Ma, et al. Expires January 17, 2013 [Page 1] Internet-Draft TEST-RESULT July 2012 include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminal test . . . . . . . . . . . . . . . . . . . . . . . . . 3 2.1. Test topology and process . . . . . . . . . . . . . . . . . 3 2.2. test cases . . . . . . . . . . . . . . . . . . . . . . . . 4 2.3. Test results and analysis . . . . . . . . . . . . . . . . . 5 3. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Security Considerations . . . . . . . . . . . . . . . . . . . . 6 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6 6. Acknowledgement . . . . . . . . . . . . . . . . . . . . . . . . 6 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 6 Ma, et al. Expires January 17, 2013 [Page 2] Internet-Draft TEST-RESULT July 2012 1. Introduction With fast development of global Internet, the demands for IP address are rapidly increasing at present. IANA announced that the global free pool of IPv4 depleted on February 3, 2011. IPv6 is only way to satisfy demands of internet development. Operators have to accelerate the process of deploying IPv6 networks in order to address IP address strains. DNS server provides name resolution and resource location services. Domain Name Service translates queries for domain names (which are meaningful to humans) into IP addresses for the purpose of locating computer services and devices worldwide. Until IPv6 completely supplants IPv4, most internet applications implement IPv4 and IPv6 protocol stacks either independently or in a hybrid form. In order to establish transition strategy, China Mobile processed some tests to make it clear that the behaviors of DNS server and terminal in a dual stack ( IPv4 [RFC0791]+IPv6 [RFC2460] ) deployment and IPv6 only deployment under the WLAN environment. This document has described detailed testing topology, cases and process. The testing results have been summarized and analyzed to provide explicit conclusions for further deployment. 2. Terminal test 2.1. Test topology and process +--------------+ +--------+ +-------+ +-------------+ |PC/smart phone|-----| AP |-----| AC |-----|DNS Server | +--------------+ +--------+ +-------+ | +-------------+ | | +-------------+ +--|Web Server | +-------------+ Figure 1: Test topology Figure 1 shows the configuration of terminal test environment. The terminals include personal computer and smartphone, As an access point, AP provided WLAN access environment. As an access controller and DHCP server, AC assigned a terminal IP address and other configuration information. The resource records in the DNS server were deployed to some different conditions. Ma, et al. Expires January 17, 2013 [Page 3] Internet-Draft TEST-RESULT July 2012 The tester make the terminal connected to AP, then input a domain name in the terminal browser and try to visit the corresponding Web page. The traffic flow between terminal and DNS/WEB server was captured by packet analyzer. For PC terminal, message flow is captured by a wireshark software in the PC. For smartphone terminal, the message flow is captured from air interface. The massage flow is analyzed and the results were summarized. 2.2. test cases 1.The ability for terminal to obtain IPv6 address The DHCP server was set to assign the terminal IPv6 address using stateless address autoconfiguration or DHCPv6, respectively. By analyzing the packet to determine whether The terminals were able to obtain IPv6 address and configuration information. 2.The behavior of DNS record query sequence We tested terminal in three network scenarios in our labotory. 1)Terminals and DNS server all have dual stack (IPv4+IPv6) address; 2)terminals have dual stack (IPv4+IPv6) address and DNS server has only IPv6 address; 3)Terminals and DNS server all have only IPv6 address; There were four deployments of resource record corresponding to a domain name in the DNS server: both A and AAAA record; only AAAA record, nonexistent DNS record and error condition. The error condition include: A record incorrect, AAAA record incorrect and both incorrect. Table 1 shows the deployments of DNS records. TABLE 1. Different deployments of DNS records Domain name DNS record condition IP address ----------------------------------------------------------------------- www.a.com both A and AAAA 10.10.100.2/2002:200:200::2 www.b.com only AAAA 2002:200:200::2 www.c.com A incorrect 10.10.100.100/2002:200:200::2 www.d.com AAAA incorrect 10.10.100.2/2002:200:200::200 www.e.com both incorrect 10.10.100.100/2002:200:200::200 In above cases, terminal was connected to WLAN network and tried to set up a TCP connection to visit a web page. The process of message Ma, et al. Expires January 17, 2013 [Page 4] Internet-Draft TEST-RESULT July 2012 interactive between terminal and DNS/WEB server was captured and analyzed. 2.3. Test results and analysis (1)The IPv6 support in the operating systems is not perfect. Some operating sysytems are not able to obtain IPv6 address and DNS using DHCPv6. (2) The sequence of DNS query depends on the operating system of terminal.In the case of dual stack, termianls will look up A and AAAA record in turn. Some terminals look up the DNS record using IPv6 address firstly, while others using IPv4 address firstly. (3) Certain operating systems have naive algorithm. In the case of assigned only IPv6 address, the terminal requests an A type record firstly. It is unnecessary for a terminal with only IPv6 address to look up an A type record. (4) Certain terminals carry unnecessary DNS queries. When there is only AAAA record in the DNS sever and terminal have dual stack addresses, certain operating system will look up an A record corresponding to a domain name several times after getting AAAA record, even after having visited the web page with AAAA record successfully. For a non-existent domain name, most terminals prefer to query all DNS records including A and AAAA, though they have received the "no such name" reply corresponding to the first query. (5) When obtaining both A and AAAA record , certain of terminals prefer using AAAA record to visit the web site. If terminals fail to set up a TCP connection using AAAA record due to incorrect AAAA record, it will retry two times with AAAA record, and then turn to use the A record. (6)Without IPv4 address, some operating sysytems can not visit the web page properly with only IPv6 address, and of course all the tested teminals can work with only IPv4 address without IPv6 address. (7)The happy eyeballs (RFC6555) mechanism is used to improve the dual-stack users experience. Amony all the tested operating sysytems, the happy eyeballs mechanism is not observed. 3. Conclusion The test results show that the IPv6 support in the operational systems are not perfect. There are many unnecessary DNS queries and traffic flows. It has the potential to cause a DNS server and Ma, et al. Expires January 17, 2013 [Page 5] Internet-Draft TEST-RESULT July 2012 network overloaded. In the development of transition strategy form IPv4 to IPv6, the test results will be taken into account and pay more attention. 4. Security Considerations It needs to be further identified. 5. IANA Considerations TBD 6. Acknowledgement Thanks for the contributions from Fan Peng. Authors' Addresses Ma Qiongfang China Mobile 32, Xuanwumenxi Ave. Xicheng District, Beijing 01719 China Email: maqiongfang@chinamobile.com Li Lianyuan China Mobile 32, Xuanwumenxi Ave. Xicheng District, Beijing 01719 China Email: lilianyuan@chinamobile.com Yang Tianle China Mobile 32, Xuanwumenxi Ave. Xicheng District, Beijing 01719 China Email: yangtianle@chinamobile.com Ma, et al. Expires January 17, 2013 [Page 6]