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Integration of Ad hoc Network and IP Network
Capabilities for Mobile Hosts
Christer Ahlund1
, Arkady Zaslavsky2
1
Luleå University of Technology, Centre for Distance-spanning Technology, Department
of Computer Science, SE-971 87 Luleå, Sweden
christer@cdt.luth.se
2
School of Computer Science & Software Engineering, Monash University,
900 Dandenong Road, Caulfield East,
Vic 3145, Melbourne, Australia
a.zaslavsky@monash.edu.au
Abstract. Mobility of user devices connecting to the
Internet is of major interest in today’s research in
networking. Users with portable devices, like laptops and
personal digital assistants (PDA), connecting to foreign
networks in the Internet want the same functionality as
when connected to the home network, as well as
accessibility through the home IP address. Ad hoc
networking is also of major importance for connectivity
between communicating mobile hosts without backbone
infrastructure and for connectivity to access points. For
the users as well as for the applications, network mobility
should be transparent. The usage of the ad hoc network or
the wired IP network should also be managed by the
networking software and hidden from applications and
users. In this paper we propose and describe an integrated
connectivity solution and its software implementation
between an ad hoc network running the Ad Hoc OnDemand
Distance-Vector Protocol and a wired IP
network where Mobile IP is used for mobility management.
With the usage of ad hoc networking, a mobile host will be
able to use multiple foreign networks to enhance the
communication performance. A proposal to multihomed
Mobile IP is presented to achieve this.
1 Introduction
The rapid developments in wireless technology have made
wireless communication appealing for connectivity to
wired IP networks and the Internet, as well as for
communicating peer-to-peer. The wireless local area
network (WLAN) standard referred to as 802.11b 1 is
widely deployed and theoretically supports the throughput
of up to 11Mbps. Another standard, 802.11a 1 supports
up to 54Mbps. The bandwidth will scale for many
applications used in desktop computers and will gradually
increase.
With the advent of high bandwidth wireless network
access, new demands for network protocol support arise.
To enable networking software to fully adopt the
possibilities with wireless network access, new
functionalities need to be added to mobile hosts (MH) and
to the wireless access network. MHs should benefit from
the dynamic behaviour of wireless computer
communication.
With wireless communication, device mobility is possible,
and to manage mobility for an MH connecting to IP
networks, where both the applications as well as the user
are unaware of the network mobility, the Mobile IP (MIP)
2 is deployed.
Another type of network becoming popular because of the
wireless capabilities in computer communications is ad hoc
networking 3. In ad hoc networks there is no such fixed
infrastructure as a wired backbone with routers. Instead, all
MHs, which are ad hoc hosts usually work as both end user
hosts and routers within the ad hoc network. The address
space in an ad hoc networks is created regardless of the
hierarchy in wired IP network topology. Some ad hoc
network proposals use clustering to create a hierarchical
network scheme, while others use a flat address space. Ad
hoc routing protocols can be classified into two major
types: proactive and reactive routing protocols 4. The
proactive routing protocols always try to maintain a route
to every host in the ad hoc network regardless of whether
user data is being sent or not. The proactive approach is the
one used in IP networks by routing protocols like RIP [5]
and OSPF [6]. In ad hoc networks where mobility might be
high, proactive routing protocols may not be optimal, since
the path created to a destination may be obsolete when the
destination is addressed. The reactive routing protocols on
the other hand create a path to a destination when packets
need to be sent there. If no user data is sent in the ad hoc
network, no routes are created. In ad hoc networks,
reactive routing protocols have proven efficient [7, 8].
Today ad hoc networks are usually seen as separate entities
without connectivity to wired IP networks. This will likely
change to make ad hoc networks part of the global
connectivity within the Internet. Also, functionalities like
multihomed ad hoc hosts as well as mobility between ad
hoc networks should be considered.
The contribution of the work proposed and described in
this paper includes:
• A gateway is proposed, connecting wired IP
networks and ad hoc networks, where the ad hoc
network uses a reactive ad hoc routing protocol.
Communication can be ad hoc with a peer or by
associating with an access point (AP) to use the
wired network. Multi-hop ad hoc connections can
be used for connectivity to an AP. MHs moving
between ad hoc networks are managed by the
MIP. By combining ad hoc networks and wired IP
networks using MIP for mobility management, a
dynamic and adaptable infrastructure is created,
enhancing the network support to the mobile
users.
• MIP is extended to enable MHs to register with
multiple APs simultaneously. This enhances the
network connectivity by enabling the MH, the
home agent (HA) and the correspondent host
(CH) to evaluate and select the best connection
for their communication.
• A prototype has been created to verify and
evaluate the gateway. The implementation uses
MIPv4 and the Ad Hoc On-Demand Distance
Vector Protocol (AODV) [9] for ad hoc networks.
Multihomed MIP is currently being integrated.
The gateway described here hosts the functionality of the
AP, the HA and the foreign agent (FA).
In section 2 we describe our design and implementation
and section 3 describes related work. Section 4 concludes
the paper and outlines future work.
2 Connecting IP Networks with Ad hoc
Networks
The connectivity between wired IP networks and ad hoc
networks integrates ad hoc networks into the global
connectivity provided by the IP. Because of the capabilities
of this connectivity, a more dynamic network
infrastructure is created. This will enable the MIP to
enhance its performance and reliability by using multiple
network connections for MHs, in what we define as
multihomed MIP.
2.1 Gobal Connectivity
Global connectivity is achieved by the layering in the
TCP/IP [10] stack. In the physical layer, different physical
equipment may be used, and in the datalink layer, different
protocols can be used (e.g. Ethernet, Token Ring, Frame
Relay). The network layer manages different datalink layer
protocols and enables connectivity between them. The
layers above the network layer (transport and application
layer) are unaware of the differences in networking
technologies, thus enabling global connectivity. When
connecting ad hoc networks with wired IP networks (see
figure 1), the differences between the two types of
networks should be considered in the network layer.
Routing and network management in wired IP networks
are based on a relatively static topology, while routing and
management in the ad hoc network need to manage a more
dynamic and frequently changing topology.
In computer networking, routing protocols need to
efficiently limit the routing information sent, in order to
reserve network resources for user data. Ad hoc networks
consisting of MHs with scarce resources should not have to
manage routing information from the wired IP network,
since this would severely impair performance in the ad hoc
network. Also, inserting frequently changing ad hoc
routing information into the wired IP network will increase
the administrative overhead.
To manage the differences in the two types of networks
and to achieve an efficient connectivity, ad hoc network is
here a (sub-) network with its own network number. By
identifying the ad hoc network with a network number, the
only routing information sent in the wired IP network is
this number and no internal ad hoc routing information. In
ad hoc networks, the only information needed by MHs to
access the wired IP network and the Internet is which
gateway to use.
The ad hoc network can be seen as a Non-Broadcast
Multiple Access (NBMA) [11] network and must be
managed by the network protocol. The ad hoc network
differs from networks like Ethernet since a packet
broadcasted by one host cannot be seen by all other hosts
in the same network in one hop. In ad hoc networks, all
MHs need to re-broadcast the packet to enable all MHs to

2.2 Multihomed Mobile IP
The most popular and widely deployed wireless
connectivity solution today, 802.11, associates an MH with
one AP at a time at the datalink layer. The MIP does not
account for multiple simultaneous connections to different
networks by MHs where connections are evaluated for
performance.
With the integration of ad hoc networks and wired IP
networks, an MH may sense multiple gateways (APs) in
the ad hoc network, and simultaneous connectivity with
multiple gateways will enhance performance and reliability
(see figure 1). The present work describes a multihomed
MIP enabling MHs to simultaneously connect to multiple
networks for enhanced performance as well as reliability.
The same home address can be used as the final destination
through all care-of addresses used by an MH. With
multiple registrations, packets sent from the MH and
packets received from the HA and the CH may use
different gateways.
First the MH will decide which networks to register with.
The registrations are stored and used by the HA to select
the care-of address for flows tunnelled from the HA to the
MH. When route optimization is used, the CH will be
informed by the HA in MIPv4 or the MH in MIPv6 about
the available care-of addresses, and it will make the
selection of which one to use.
The gateway(s) selection will be managed at the network
layer. An MH is then able to decide which gateway(s) to
use on other criteria than the signal-to-noise ratios. In the
work described here, the delay is used to make the
selection.
Multihomed MH
Ad hoc network
BSS
BSS
Fig. 1. An ad hoc subnet with a multihomed MH.
2.3 Design and Implementation
In the design and implementation described below, we
make use of MIPv4, and the AODV routing protocol
within the ad hoc network.
In this section we describe:
• How MIPv4 messages are managed in the ad hoc
network.
• How an MH decides what FAs to register with, if
it knows several.
• How a destination address from the ad hoc
network is found in the ad hoc network or in the
Internet.
• How multihoming in MIP is managed.
An MH will run the AODV protocol to communicate with
peers and to access the wired IP network through the
gateway (also running AODV). To manage the mobility of
MHs between ad hoc networks, MHs as well as the
gateways run the MIP, where the software for the FA and
HA runs in the gateway.
For the MIP messages specified to be sent link-local in a
LAN, with a TTL value of 1, we have changed the value to
indicate the size of the ad hoc network or the length in
hops to an MH.
We have made the AODV protocol MIP-aware to
recognize MIP messages so that ad hoc hosts (MH and
gateway) can install routes based on the messages. Hosts
forwarding agent advertisements will install a route to the
FA. When an MH then registers with an FA by sending a
registration request to the agent, a route will be available,
without the need to do an explicit RREQ for the FA. The
registration request creates a route for the registration
reply, and the agent solicitation message creates a route for
the unicasted agent advertisement.
An MH discovers a path to a destination by sending an
route request (RREQ) for the destination. If the destination
is known to be outside the ad hoc network, the gateway
replies with a proxy RREP (ProxyRREP) to the source.
The packets will then be sent to the gateway that forwards
them on the wired network. For a destination within the ad
hoc network, the gateway will function as an ad hoc host
forwarding the RREQ.
For a gateway to know which hosts are in the ad hoc
network, the AODV protocol requires information of the
visitor list in the FA, and all hosts homed in the ad hoc
network have to have the same network number as the
gateway connecting to the ad hoc network. These
requirements are the same as for a LAN in IP networks
managing mobility. When a route is requested for a
destination with a network number different from the ad
hoc network, the visitor list is searched by the AODV
process to see if the destination is available in the ad hoc
network. If the destination is not within the network, the
gateway sends a ProxyRREP to the source. If the
destination is a foreign MH visiting the ad hoc network,
normal AODV operations are used to discover the
destination within the network. Figure 2 illustrates this.

Fig. 2. The process in the gateway to manage AODV
RREQ messages.
A ProxyRREP is also sent if a destination homed in the ad
hoc network is connected to a foreign network. The HA
functionality used is as specified in MIPv4. Packets
coming to the gateway will be processed as shown in
figure 3.
To manage several FAs covering an ad hoc network there
is a need to synchronize the visitor information between
the FAs. Without synchronization, a gateway may
conclude that a destination is within the wired IP network
and send a ProxyRREP to the source, while the destination
is in fact within the ad hoc network but registered with
another FA.
Packet input
Packet from Internet Packet from ad hoc network
Dest. at foreign
network / Tunnel
packet
D est. is in Internet /
Se nd to default
Dest. is in ad hoc gatew ay
network
Dest. at home
ε
Route
available/
Forward
packet
No route/
Standard AODV
Fig. 3. The flow in the gateway to process an incoming
packet.
The FAs synchronize their visitor lists using the wired IP
network to relieve the ad hoc network, and the information
is synchronized when an entry is added or deleted from the
visitor list in a gateway. All gateways will thus be able to
see if a visiting host is within the ad hoc network even if it
is not registered with the gateway receiving the RREQ.
The HA binding cache does not have to be synchronized
between the gateways since the gateway responding with a
ProxyRREP will be the gateway acting as an HA for the
MH connected to a foreign network. Other gateways will
‘believe’ that the MH is in the ad hoc network.
When several FAs serve an ad hoc network, an MH must
be able to choose the best FA(s) to register with. Also, an
MH may discover multiple ad hoc networks. This is
managed by multihomed MIP.
Multihoming is managed by the MIP and hidden from the
IP routing and ad hoc routing, making IP routing protocols
like RIP and OSPF as well as AODV unaware of this. For
a sender, multihomed MIP can be considered an any-cast
approach [14] where a sender relies on the network
protocol to find the best available destination for the
packets. The best available destination for packets will be
one of possibly multiple care-of addresses used by an MH.
In IPv6, an any-cast address is used to reach the best
available destination (server) among multiple destinations
supporting the service required. The approach in this paper
for a sender to any-cast address an MH, is that the MH’s
home address is used to locate the best care-of address
(gateway). The difference from the any-cast approach in
IPv6 is that it is address-based instead of server-based and
the destination will be the same host.
Since no routing information is redistributed between the
wired IP network and the ad hoc network the, total distance

The MH must decide which foreign network(s) to register
with. An MH receiving advertisements from foreign
networks will monitor the available networks and measure
the round trip time (RTT) to the gateway, see figure 4. This
time is recorded for each advertisement and the gateway(s)
with the smallest metrics calculated from the RTTs are
registered at the HA. An MH is configured with the
maximum number of networks to register.
The HA will have multiple bindings for an MH’s home
address registering multiple care-of addresses. Based on
the RTT between the HA and the MH, one of the care-of
addresses will be installed as the tunnel end-point to the
MH. The measuring of RTTs is based on the registration
messages sent between the MH and the HA (see figure 5).
Reg.request
N-bit clear / N-bit set
Normal MIP
Binding exists /
update binding
Get RRT extension/
calculate metrics
Metric s + threshold < metric s
of c urrent tunnel / install new
tunne l
New binding / add
binding
False
Send reg.reply
Fig. 5. Processing of registration requests in the HA.
A CH sending packets to an MH without route
optimization will send them to the MH’s home network,
where the HA will make the selection of which care-of
address to use to forward the packets. With route
optimization, the CH will send the packets to the MH
without using the HA and will itself tunnel the packets to
the selected care-of address. The care-of address
information is sent by the HA to the CH. In multihomed
MIP, multiple care-of addresses may be sent. The selection
at the CH for which care-of address to use can be based on:

• longest prefix match
• first address received
• delay
  The choice of care-of address is based on individual
  selections by the HA, the CH and the MH for packets sent
  by them. In a scenario where an MH has registered three
  care-of addresses and there are two CHs, one using the HA
  to communicate with the MH and the other using route
  optimization, three different gateways may be used: one by
  the HA, another by the CH using route optimization and
  the third by the MH to send packets (see figure 6).
  The MH keeps a list of all foreign networks with valid
  advertisements and some of the entries will be in a second
  list identifying the networks it is registered with.
  HA
  CH
  MH
  Home network
  Foreign Network s
  Internet router
  FAs, APs
  CH
  FAs, APs
  Fig. 6. A multihomed connectivity where the HA, CN and
  MH make their own selections of which care-of address to
  use.
  2.4 Implementation
  The gateway as well as the MHs run the MIP software and
  the AODV software (see figure 7). The MIP software used
  is the HUT distribution [22] and the AODV software is a
  distribution from Uppsala University[23]. The operating
  system used is Linux [24].
  MIPv4 AODV
  Forwarding
  tab lel
  Forward ing
  process
  User sp ace
  Kernel
  Fig. 7. The processes in a mobile host and their
  relationship, using the forwarding table in the kernel.
  The software in the gateway looks as in figure 7 with the
  extension of the shared memory between the MIP and the
  AODV processes, so that the AODV process will be
  informed of visiting MHs. If the gateway hosts an HA as
  well, the shared memory will also contain the hosts homed
  in the ad hoc network and connected to a foreign network.
  The MIP and AODV software operates by modifying the
  forwarding table within the Linux kernel. In the kernel the
  forwarding process manages packets by using this
  information.
  The MH keeps a list of all FAs sending agent
  advertisements, and registers the care-of address at the HA
  for the FAs supporting the smallest metrics. To select the
  FA(s) to register with, the MH sends an Internet Control
  Message Protocol (ICMP) echo request to the FAs it
  knows about. To calculate the metrics used for comparison
  the Jacobson/Karels algorithm [15] is used (see formula 1).
  The algorithm accounts for both the RTT and the deviation
  in the measurements.
  Difference = SampleRTT – EstimatedRTT. (1)
  EstimatedRTT = EstimatedRTT + (δ x Difference).
  Deviation = Deviation + δ(|Difference| - Deviation).
  Metric = µ x EstimatedRTT + φ x Deviation.
  To avoid rapid changes resulting in flapping of the care-of
  addresses registered at the HA, a new FA is only chosen if
  the value differs beyond a certain threshold.
  In MIP, an MH receiving an agent advertisement assumes
  the previous link layer sender to be the FA, and uses this
  address for its registration request. This must be modified
  to function in ad hoc networks, otherwise the MH will
  believe an intermediate host in the ad hoc network
  forwarding the agent advertisement to be the FA. We
  reserve the first care-of address field in the agent
  advertisement for the FA address within the ad hoc
  network (see figure 8). The MH can then discover the
  address of an FA multiple hops away.
  type length sequence number
  registration lifetime R B M F M G V reserved
  foreign agent address on the ad hoc network
  zero or more care-of addresses
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  Fig. 8. The modified agent advertisement extension for the
  ad hoc network…
  The agent solicitation message is also modified to function
  in the ad hoc network for the same reason as the agent
  advertisement. The solicitation message used in the
  standard MIP is the same as the router solicitation
  message. Figure 9 shows the agent solicitation extension
  added to the router solicitation.
  source address
  type reserved
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  Fig. 9. The agent solicitation extension added to the router
  solicitation.
  To register a care-of address at the HA, a registration
  request is sent, and to enable the HA to distinguish
  between a non-multihomed and a multihomed registration,
  an N-flag is added to the registration request (see figure
  10). An HA receiving the registration request with an Nflag
  will keep the existing bindings for the MH. For the
  HA to be able to select a care-of address when forwarding
  packets to the MH, the RTT to the MH through different
  care-of addresses is measured. The MH monitors the time
  between registration requests and registration replies and
  calculates the RTT. The RTT is added as an extension in
  the next registration request. The HA will maintain all
  registrations for an MH and based on the metrics it will
  install a tunnel into the forwarding table with the care-of
  address with the smallest metrics.
  extensions
  typ e
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  S B D M G V P N lifetime
  home address
  home agent
  care-of address
  identification
  Fig. 10. The modified registration request message.
  The MH will maintain multiple registrations with different
  FAs as well as keep control of available FAs not registered
  with.
  For route optimization, the binding update sent from the
  HA to a CH is shown in figure 11. The binding update is
  extended to carry multiple care-of addresses. The CH will
  install a tunnel to one of the MH’s care-of addresses in its
  forwarding table. The decision of which care-of address to
  install as the tunnel end-point in the forwarding table is
  based on the longest prefix match. If two care-of addresses
  have the same match, the first listed will be used.
  When the binding is about to expire, the CH sends a
  binding request to the HA, and the HA will reply with the
  current bindings of an MH to the CH.
  typ e
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  A I M G reserved lifetime
  mobile host home address
  identification
  One or more care-of addresses
  Fig. 11. The modified binding update message.
  3 Related work
  In [16] a work is described to modify RIP for ad hoc
  networks and with MIP. This approach uses a proactive ad
  hoc routing protocol less efficient in ad hoc networks. In
  [17-20] proposals for connections between MIP and
  AODV are made. In [19] MIPv4 and AODV are connected
  so that MIP messages will be managed in the ad hoc
  network. The question of how to choose between multiple

FAs is not addressed, and an MH in the ad hoc network has
to discover by itself if a destination is within the ad hoc
network or not. If the gateway ‘thinks’ it can receive the
destination, it replies with an FA RREP (like the
proxyRREP). But before an MH can use the gateway, it
first needs to conclude that the destination is not within the
ad hoc network and this will delay the connection setup
time. MIPv6 management with AODV is proposed in [18]
using the ND protocol. The same approach for destinations
in the IP network is taken as in [19] and it is proposed that
router advertisements should not be sent without router
solicitation. However, in [17] measurements show that it is
more efficient to use the normal MIP behaviour where
advertisements are sent without solicitations. In [17] and
[20] an approach to choosing between multiple FAs is
described, and the selection in made based on the hop
count between the FA and the MH. Hop count may
however not be the best way to measure which FA to
register with since network load is not considered. In [21]
MIP and the ad hoc routing protocol DSR are addressed.
In MIPv4, an option for simultaneous bindings is proposed
for sending packets to multiple care-of addresses for an
MH. Packets will be duplicated at the HA and one copy
sent to each registered care-of address, so that packets can
be received through multiple APs. This option was
proposed to decrease the number of dropouts of packets
during handover, and for an MH with bad connections to
APs to receive the same packet through several APs, with
an increased probability of a good connection. The solution
does not however enable network layer decisions of the
best connection to use, and it will waste resources in the ad
hoc network.
In the current specification of MIPv6, all traffic uses the
same care-of address. This prevents the MIP from fully
utilizing the dynamics within global connectivity including
ad hoc networking, and should therefore be altered.
4 Conclusion and further work
In this article we propose and describe an integrated
connectivity solution and its implementation connecting IP
networks and ad hoc networks running the reactive AODV
routing protocol, where MIP is used to manage mobility.
The software supports the creation of areas covered by
gateways connecting wireless MHs to the Internet. MHs
will be able to communicate peer-to-peer or with hosts in
the IP network. Our approach proposes a new way to
locate a destination inside the ad hoc network or in the IP
network, and the selection of FA(s) based on the RTT
between the MH and the FA.
MIP is extended to manage multiple simultaneous
connections with foreign networks. Based on the registered
care-of addresses, multiple paths can be used for packets to
and from an MH. Enhanced throughput and a more reliable
connection are achieved. The current prototype is based on
MIPv4 but will in the next phase be deployed on MIPv6 as
well.
To avoid sending explicit ICMP echo requests in the ad
hoc network to measure the RTT, a study will be done on
whether only the jitter in arrival time between received
agent advertisements can be used to decide the
performance of a connection to a gateway. A study will
also be performed on the impact of the delay between the
measurement of the RTT and the time the HA receives the
information, since the RTT is sent one registration request
later than when it was measured.
We are currently running performance tests and collecting
statistics. We will compare our proposal to those in [17]
and [20]. The performance and the time to discover a
destination in the ad hoc network or in the IP network will
be evaluated and compared to the proposals in [17-20].
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21. Y. Sun, E. M. Belding-Royer, C. E. Perkins, “Internet
    Connectivity for Ad hoc Mobile Networks”
    International Journal of Wireless Information
    Networks special issue on “Mobile Ad Hoc Networks
    (MANETs): Standards, Research, Applications”, to be
    published.
22. J. Broch, D. A. Maltz, and D. B. Johnson. “Supporting
    Hierarchy and Heterogeneous Interfaces in Multi-Hop
    Wireless Ad Hoc Networks,” in Proceedings of the
    Workshop on Mobile Computing held in conjunction
    with the International Symposium on Parallel
    Architectures, Algorithms, and Networks, June 1999.
23. Dynamics-HUT Mobile IP. Available:
    http://www.cs.hut.fi/Research/Dynamics/.
24. AODV-UU.
    Available:http://www.docs.uu.se/~henrik1/aodv/.
25. Linux. Available: http://www.linux.org. # 欢迎使用Markdown编辑器

你好！ 这是你第一次使用 Markdown编辑器 所展示的欢迎页。如果你想学习如何使用Markdown编辑器, 可以仔细阅读这篇文章，了解一下Markdown的基本语法知识。

新的改变

我们对Markdown编辑器进行了一些功能拓展与语法支持，除了标准的Markdown编辑器功能，我们增加了如下几点新功能，帮助你用它写博客：

1. 全新的界面设计 ，将会带来全新的写作体验；
2. 在创作中心设置你喜爱的代码高亮样式，Markdown 将代码片显示选择的高亮样式 进行展示；
3. 增加了 图片拖拽 功能，你可以将本地的图片直接拖拽到编辑区域直接展示；
4. 全新的 KaTeX数学公式 语法；
5. 增加了支持甘特图的mermaid语法¹ 功能；
6. 增加了 多屏幕编辑 Markdown文章功能；
7. 增加了 焦点写作模式、预览模式、简洁写作模式、左右区域同步滚轮设置 等功能，功能按钮位于编辑区域与预览区域中间；
8. 增加了 检查列表 功能。

功能快捷键

撤销：Ctrl/Command + Z
重做：Ctrl/Command + Y
加粗：Ctrl/Command + B
斜体：Ctrl/Command + I
标题：Ctrl/Command + Shift + H
无序列表：Ctrl/Command + Shift + U
有序列表：Ctrl/Command + Shift + O
检查列表：Ctrl/Command + Shift + C
插入代码：Ctrl/Command + Shift + K
插入链接：Ctrl/Command + Shift + L
插入图片：Ctrl/Command + Shift + G

合理的创建标题，有助于目录的生成

直接输入1次#，并按下space后，将生成1级标题。
输入2次#，并按下space后，将生成2级标题。
以此类推，我们支持6级标题。有助于使用TOC语法后生成一个完美的目录。

如何改变文本的样式

强调文本 强调文本

加粗文本 加粗文本

标记文本

删除文本

引用文本

H₂O is是液体。

2¹⁰ 运算结果是 1024.

插入链接与图片

链接: link.

图片:

带尺寸的图片:

当然，我们为了让用户更加便捷，我们增加了图片拖拽功能。

如何插入一段漂亮的代码片

去博客设置页面，选择一款你喜欢的代码片高亮样式，下面展示同样高亮的 代码片.

// An highlighted block
var foo = 'bar';

生成一个适合你的列表

• 项目
  • 项目
    • 项目

1. 项目1
2. 项目2
3. 项目3

• 计划任务
• 完成任务

创建一个表格

一个简单的表格是这么创建的：

项目	Value
电脑	$1600
手机	$12
导管	$1

设定内容居中、居左、居右

使用:---------:居中
使用:----------居左
使用----------:居右

第一列	第二列	第三列
第一列文本居中	第二列文本居右	第三列文本居左

SmartyPants

SmartyPants将ASCII标点字符转换为“智能”印刷标点HTML实体。例如：

TYPE	ASCII	HTML
Single backticks	'Isn't this fun?'	‘Isn’t this fun?’
Quotes	"Isn't this fun?"	“Isn’t this fun?”
Dashes	-- is en-dash, --- is em-dash	– is en-dash, — is em-dash

创建一个自定义列表

Markdown

Text-to- HTML conversion tool

Authors

John

Luke

如何创建一个注脚

一个具有注脚的文本。²

注释也是必不可少的

Markdown将文本转换为 HTML。

KaTeX数学公式

您可以使用渲染LaTeX数学表达式 KaTeX:

Gamma公式展示 $\Gamma (n)=(n-1)!\forall n\in \mathbb{N}$ 是通过欧拉积分

$$\Gamma (z)={\int }_0^{\infty }{t}^{z-1}{e}^{-t}dt.$$

你可以找到更多关于的信息 LaTeX 数学表达式here.

新的甘特图功能，丰富你的文章

• 关于 甘特图 语法，参考 这儿,

UML 图表

可以使用UML图表进行渲染。 Mermaid. 例如下面产生的一个序列图：:

这将产生一个流程图。:

• 关于 Mermaid 语法，参考 这儿,

FLowchart流程图

我们依旧会支持flowchart的流程图：

• 关于 Flowchart流程图 语法，参考 这儿.

导出与导入

导出

如果你想尝试使用此编辑器, 你可以在此篇文章任意编辑。当你完成了一篇文章的写作, 在上方工具栏找到 文章导出 ，生成一个.md文件或者.html文件进行本地保存。

导入

如果你想加载一篇你写过的.md文件或者.html文件，在上方工具栏可以选择导入功能进行对应扩展名的文件导入，
继续你的创作。

---

1. mermaid语法说明 ↩︎

2. 注脚的解释 ↩︎