• Reasons for sending a SubscribeEventgroupNegativeAcknowledgment include:
  发送SubscribeEventgroupNegativeAcknowledgement的原因包括：
  • Combination of Service ID, Instance ID, Eventgroup ID, and Major Version is unknown
    服务ID，实例ID，事件组ID和主要版本的组合未知
  • Required TCP-connection was not opened by client
    必需的TCP连接未由客户端打
  • Problems with the references options occurred (wrong values, missing endpoint, or conflicting endpoints)
    发生引用选项问题（错误值，缺少端点或冲突端点）
  • Resource problems at the Server .
    服务器的资源问题。
• If a SubscribeEventgroup entry referencing two conflicting Endpoint Options (UDP or TCP) is received then a SubscribeEventgroupNack shall be generated. Endpoint options are considered conflicting if they are of the same type but hold different values, like different IP or Port number.
  如果收到了引用两个冲突的Endpoint option（UDP或TCP）的SubscribeEventgroup entry，则会生成一个SubscribeEventgroupNack。如果Endpoint options属于相同类型但持有不同的值（如不同的IP或端口号），则认为endpoint option存在冲突。

• The SubscribeEventgroupNegativeAcknowledgment entry type shall be used to indicate that SubscribeEventgroup entry was NOT accepted. It shall be always sent instead of a SubscribeEventgroupAck if such an error occurred.
  SubscribeEventgroupNegativeAcknowledgement entry类型应用于表明SubscribeEventgroup entry不被接受。如果发生此类错误，它应始终被发送，而不是SubscribeEventgroupAck entry。
• Service ID, Instance ID, Major Version, Eventgroup ID, Counter, and Reserved shall be the same value as in the subscribe that is being answered.
  服务ID，实例ID，主要版本，事件组ID，计数器和保留的值应与正在应答的SubscribeEventgroup Entry中的值相同。
• The TTL shall be set to 0x000000.
  TTL应设置为0x000000。

StopSubscribeEventgroup entry

• StopSubscribeEventgroup entries shall set the entry fields exactly like the SubscribeEventgroup entry they are stopping, except the TTL field.
  StopSubscribeEventgroup条目应与其正在停止的SubscribeEventgroup entry的设置一样，TTL除外。

• The TTL shall be set to 0x000000.
  TTL应设置为0x000000。

• A Stop Subscribe Eventgroup Entry shall reference the same options the Subscribe Eventgroup Entry referenced. This includes but is not limited to Endpoint and Configuration options.
  Stop Subscribe Eventgroup Entry应引用其对应的Subscribe Eventgroup Entry相同的options 。 这包括但不限于Endpoint和Configuration option。

SubscribeEventgroupAck entry

• To acknowledge a SubscribeEventgroup entry, the SubscribeEventgroupAck entry shall be used and shall be used with the values as in the SubscribeEventgroup entry it answers.
  要确认SubscribeEventgroup entry，应使用SubscribeEventgroupAck entry，并应与其回复的SubscribeEventgroup entry中的值一致。

• Service ID, Instance ID, Major Version, Eventgroup ID, TTL, Counter, and Reserved shall be the same value as in the Subscribe that is being answered.
  服务ID，实例ID，主要版本，事件组ID，TTL，计数器和保留位应与正在应答的Subscribe中的值相同。

• A SubscribeEventgroupAck entry shall set the TTL field to the value of the SubscribeEventgroup entry, it acknowledges.
  SubscribeEventgroupAck entry应将TTL字段设置为它确认的SubscribeEventgroup entry的值。

• SubscribeEventgroupAck entries referencing events and notification events that are transported via multicast shall reference an IPv4 Multicast Option and/or and IPv6 Multicast Option. The Multicast Options state to which Multicast address and port the events and notification events will be sent to.
  针对通过multicast传输的events和notification events的SubscribeEventgroupAck entry应引用IPv4 Multicast Option和/或IPv6 Multicast Option 。Multicast Option表明notification event将会发送到哪个Multicast地址和port口。

• The Counter field in the Type 2 Entry format is used to differentiate different Subscribe Eventgroups to otherwise identical Eventgroups (i.e. same Service ID, same Instance ID, same Eventgroup ID, and same Major Version). The Counter field shall be reflected by the Server to the Subscribe Eventgroup Ack and Nack entries.
  类型2 Entry格式中的Counter字段用于将Subscribe Eventgroup和其他相同的Eventgroup进行区分（即相同的 Service ID，相同的 Instance ID，相同的Eventgroup ID和相同的Major Version ）。 Counter字段应由服务器反映到Subscribe Eventgroup Ack和Nack条目。

• If identical Consumed Eventgroups are configured with different Endpoints, then the SD shall use the Counter to differentiate the different Subscriptions. The value of the Counter can be determined by the implementation.
  如果相同的Consumed Eventgroups配置了不同的Endpoint，则SD应使用Counter去区分不同的Subscription。 Counter的值可以由具体实现来确定。

• Note注意:
  A width of 4 bits limits this to 16 different Subscriptions to the same Eventgroup.
  4位宽度将此限制为同一个Eventgroup最多有16个不同的Subscription。

• SubscribeEventgroup entries shall have the TTL field set to the configured value (configuration parameter SdClientTimerTTL of SdConsumedEventGroup) and the SubscribeEventgroupAck entry shall use the TTL value of the SubscribeEventgroup entry it acknowledges.
  SubscribeEventgroup条目应将TTL字段设置为配置值（SdConsumedEventGroup的配置参数SdClientTimerTTL），而SubscribeEventgroupAck条目应使用它所确认的SubscribeEventgroup条目的TTL值。

• A StopSubscribeEventgroup (type 0x06), and SubscribeEventgroupNack (type 0x07) entry shall set the TTL field to 0x000000.
  StopSubscribeEventgroup（类型0x06）和SubscribeEventgroupNack（类型0x07）条目应将TTL字段设置为0x000000。

• [SWS_SD_00300]⌈ Eventgroup entries shall set the Reserved fields to 0x00 and 0x000.
  事件组条目应将保留字段设置为0x00和0x000。

• Eventgroup entries shall carry the options as configured.
  事件组条目应包含已配置的option。

OfferService entry

• Service ID shall be set to the Service ID of the Service Instance offered.
  服务ID应设置为所提供服务实例的服务ID。

• Instance ID shall be set to the Instance ID of the Service Instance offered.
  实例ID应设置为提供的服务实例的实例ID。
• Example示例：
  ECU1 offers Service 0x1234 with Instance 0xabcd. This instance is in Main Phase. ECU2 send out find with Service ID 0x1234 and Instance ID 0xFFFF. ECU1 shall answer with Offer (Service ID 0x1234, Instance ID 0xabcd).
  ECU1提供Instance为0xabcd的Serice 0x1234。这个实例处于Main Phase。 ECU2发送带有 Service ID 0x1234和 Instance ID 0xFFFF的FindService Entry。 ECU1应使用OfferService Entry回答（Service ID 0x1234，Instance ID 0xabcd）。

• Major Version shall be set to the Major Version of the Service Instance offered.
  Major Version应设置为所提供服务实例的Major Version 。
• Note注意：
  Since SdServerServiceMajorVersion can be only a value up to 0xFE, the value 0xFF (any) cannot occur in an OfferService entry.
  由于SdServerServiceMajorVersion最大只能是0xFE的值，因此在OfferService Entry中不能出现值0xFF（任何）。

• Minor Version shall be set to the Minor Version of the Service Instance offered.
  次要版本应设置为所提供服务实例的次要版本。

• TTL shall be set to the lifetime of the Service Instance. After this lifetime the Service Instance shall considered not been offered.
  应将TTL设置为服务实例的生命周期。在生命周期结束之后，服务实例应被视为未提供。
• If TTL is set to 0xFFFFFF, the OfferService entry shall be considered valid until the next reboot.
  如果TTL设置为0xFFFFFF，则OfferService条目应被视为有效，直到下一次重启。

• OfferService entries shall always reference at least an IPv4 or IPv6 Endpoint Option to signal how the service is reachable.
  OfferService条目应始终引用至少一个IPv4或IPv6 Endpoint Option ，以表明服务如何得到。
• For each L4 protocol needed for the service (i.e. UDP and/or TCP) an IPv4 Endpoint option shall be added if IPv4 is supported.
  对于服务所需的每个L4协议（即UDP和/或TCP），如果支持IPv4，则应添加IPv4端点选项。
• For each L4 protocol needed for the service (i.e. UDP and/or TCP) an IPv6 Endpoint option shall be added if IPv6 is supported.
  对于服务所需的每个L4协议（即UDP和/或TCP），如果支持IPv6，则应添加IPv6端点选项。
• The IP addresses and port numbers of the Endpoint Options shall also be used for transporting events and notification events.
  端点选项的IP地址和端口号也应该用于传送事件和通知事件。
• In the case of UDP this information is used for the source address and the source port of the events and notification events.
  对于UDP，此信息用于事件和通知事件的源地址和源端口。
• In the case of TCP this is the IP address and port the client needs to open a TCP connection to in order to receive events using TCP.
  在TCP的情况下，这些IP地址和端口是客户端所需要的，用来建立TCP连接以接收Event。

FindService entry

• Service ID shall be set to the Service ID of the service that shall be found.
  服务ID应设置为应找到的服务的Service ID

• Instance ID shall be set to 0xFFFF, if all Service Instances shall be returned.
  如果返回所有服务实例，则实例ID应设置为0xFFFF。
• It shall be set to the Instance ID of a specific Service Instance, if just a single Service Instance shall be returned.
  如果仅返回一个服务实例，则应将其设置为特定服务实例的Instance ID。

• Major Version shall be set to 0xFF, that means that services with any version shall be returned. If set to value different than 0xFF, services with this specific major version shall be returned only.
  主要版本应设置为0xFF，这意味着应返回任何版本的服务。如果设置为不同于0xFF的值，则至于具有此特定主版本的服务被返回。
• Note注意：
  It is expected that the Major Version on client side is configured to a specific value in normal operation since the client should look for an specific interface version. Different Major Versions are not compatible to each other.
  由于客户端应该查找特定的接口版本，因此期望客户端的主要版本在正常操作中配置为特定值。不同的主要版本互不兼容。

• Minor Version shall be set to 0xFFFF FFFF, that means that services with any version shall be returned. If set to a value different to 0xFFFF FFFF, services with this specific minor version shall be returned only.
  次要版本应设置为0xFFFF FFFF，这意味着应返回任何版本的服务。如果设置为不同于0xFFFF FFFF的值，则仅返回具有此特定次要版本的服务。
• Note注意：
  It is expected that the Minor Version on client side is configured to 0xFFFF FFFF in normal operation since the client should accept all different Minor Versions. Different Minor Versions shall be compatible to each other.
  由于客户端应该接受所有不同的次要版本，所以希望客户端的次要版本在正常操作中配置为0xFFFF FFFF。不同的次版本应该相互兼容。

• TTL shall be set according to the configuration.
  TTL应根据配置进行设置。
• If TTL is set to 0xFFFFFF, the SubscribeEventgroup entry shall be considered valid until shutdown (i.e. next reboot).
  如果TTL设置为0xFFFFFF，则SubscribeEventgroup条目应被视为有效，直至关闭（即下次重新启动）。

• FindServer entries shall never reference Endpoint or Multicast Options. They shall reference configuration options, if configured to do so.
  FindServer条目不得引用Endpoint或Multicast option。他们应引用configuration options ，如果配置如此。

• All entries concerning Services (FindService, OfferService, StopOfferService) shall be of Entry Format Type 1.
  所有service entry（FindService，OfferService，StopOfferService）都应该使用Entry Format Type 1 。

• An Instance ID of 0xFFFF shall mean any possible instances and are not allowed for OfferService and StopOfferService entries.
  Service ID为0xFFFF表示任何可能的instance，但不允许是OfferService和StopOfferService entry。

• FindService entries shall carry Service ID, Service Instance ID, Major Version, and Minor Version as configured in SdClientServiceID, SdClientServiceInstanceID, SdClientServiceMajorVersion, and SdClientServiceMinorVersion.
  FindService条目应包含在SdClientServiceID，SdClientServiceInstanceID，SdClientServiceMajorVersion和SdClientServiceMinorVersion中配置的 service ID，service instance ID，major version和minor version。
• OfferService and StopOfferService shall carry Service ID, Service Instance ID, Major Version, Minor Version, and as configured in SdServerServiceID, SdServerServiceInstanceID, SdServerServiceMajorVersion, and SdServerServiceMinorVersion.
  OfferService和StopOfferService应包含Service ID，Servcie instance ID， major version，minor version以及在SdServerServiceID，SdServerServiceInstanceID，SdServerServiceMajorVersion和SdServerServiceMinorVersion中配置的内容。

• All entries concerning Services (FindService, OfferService and StopOfferService shall carry – i.e. reference – the options as configured.
  有关service（FindService，OfferService和StopOfferService）的所有entry都应带有 – 即引用 – 所配置的option
• A StopOfferService (type 0x01), shall carry – i.e. reference – the same options as the entries trying to stop.
  StopOfferService（类型0x01）应携带 – 即引用 – 与entry试图停止的相同的option。

• FindService entries shall carry the TTL as configured in SdClientTimerTTL.
  FindService entry应携带在SdClientTimerTTL中配置的TTL。
• OfferService entries shall carry the TTL as configured in SdServerTimerTTL.
  OfferService entry应携带SdServerTimerTTL中配置的TTL。
• A StopOfferService (type 0x01) entry shall set the TTL field to 0x000000.
  StopOfferService（type 0x01）entry 应将TTL字段设置为0x000000。

• ECUs shall distribute available Service Instances and Service Instances needed as well as the Eventgroups of these Service Instances. For this purpose, they exchange entries using Service Discovery messages. This chapter describes how these entries are encoded to offer and find services as well as find and subscribe Eventgroups.
  ECU应分发已有的的Service Instances和所需的Service Instances以及包含这些Service Instances的Eventgroup。 为此，他们使用Service Discovery消息来交换entry。 本章介绍如何对这些条目进行编码以offer和find服务以及find和subscribe 这些Eventgroups。

• The following overview table shows to which value the Type field and the TTL field have to be set:
  以下概览表显示了Type字段和TTL字段必须设置为哪个值：