Example: Configures the maximum response time of IGMP snooping queries. The kernel in Red Hat Enterprise Linux supports IGMPv3. An IGMP proxy device maintains a group membership database, which stores the group memberships on all the router interfaces. When enabled, the IGMP Snooping switch starts working as IGMP Snooping does, and then, when the switch retrieves an IGMP query from a router, it promptly responds with a report according to its status. Internet Group Management Protocol (IGMP) proxy can be used to implement multicast routing. (Optional) In the Privileged EXEC mode of the switch, save the configured settings to the startup configuration file by entering the following: Figure 1: Example IGMP Snooping Topology. 0. A proxy device forwards packets received on any downstream interface to the upstream interface, and to each downstream interface other than the incoming interface based upon the downstream interfaces' subscriptions and whether or not this proxy device is the IGMP/MLD Querier on each interface. A proxy device MAY use a forwarding cache in order IGMP Snooping is a feature for switches to learn what multicast groups are needed on which ports. 8. It is forwarding IGMP frames and is commonly used when there is no need for a more advanced protocol like PIM. This prevents the switch from flooding multicast streams on ports that have no members for these multicast addresses. This must be configured directly on the FortiSwitch. Switch (config)# ip igmp snooping querier timer expiry 180 (Optional) Sets the length of time until the IGMP querier expires. These diagrams shows example networks with Firebox interfaces configured as RP candidates. When disabled, the IGMP queries in VLAN and the reports from hosts are flooded. y multicast address (in this address, x. Multicast Listener Discovery (MLD) snooping constrains the flooding of IPv6 multicast traffic on VLANs. arrow_forward. 2, you could use the CLI to enable IGMP proxy on a system-wide basis. IGMP snooping monitors the Layer 3 IGMP traffic. 또한, 호텔 같은 곳에서 유료 방송에 대한 인증 절차를 IGMP proxy 에서 처리하는데, 이를 이용해서 유료 방송에 대한 과금 처리를 수행할 수 있게 된다. A1 connects to H11, H12, H13. The device supports IGMP version 3. 3. IGMP-snooping querier and per-VLAN IGMP-snooping proxy configuration 7. IGMP Snooping is an Ethernet Virtual Circuit (EVC)-based feature set. When enabled, the IGMP snooping querier restarts if you configure an IP address. Step 2. This is not a vendor How to Configure IGMP Snooping. switch (config-vlan)# ip igmp snooping mrouter vpc-peer-link. 100 from one of the hosts—for example, Host B. The IGMP on/off box on the web UI is used for whether you need to make IGMP work on IGMP V3 only, which is required by several IPTV service providers. The exact process may vary depending on the switch model and vendor. The way access switches using IGMP snooping decide to forward multicast data to hosts is relatively obvious. Enters interface configuration mode. Learn how to customize IGMP for multicast routing on Cisco ASR 1000 Series routers. Mar 2, 2023 · Here are some top considerations to keep in mind when configuring IGMP snooping: Enable IGMP snooping on all switches: To ensure proper multicast traffic forwarding and filtering, IGMP snooping should be enabled on all switches in the network. Odd - Router was found powered off (not pingable, not lights) Pressed the power button out/in to power on. Apr 20, 2023 · IGMP is a protocol used by network equipment to specify which devices should receive which multicast groups. When the DVS is upgraded to 7. Configures a static connection to a virtual port channel (vPC) peer link. 1 to solicit multicast groups with active multicast receivers. The IGMP Snooping Table displays all of the VLANs currently configured on the switch, as well as their IGMP settings. 가입자와 IGMP proxy 간의 논리적인 거리는 짧게 유지한다면, 채널 전환 딜레이도 그만큼 감소시킬 수 있다. to/2oSID88) with an explanation of IGMP Proxying and IGMP Snooping. age 43-14 NoteTo use IGMP snooping, configure a Layer 3 interface in the subnet for multicast routing (see Chapter 42, “IPv4 Multicast Layer 3 Features”) or enable the IGMP snooping querier in the subnet (see the “Enabling the IGMP Snooping Querier” sec. We would like to show you a description here but the site won’t allow us. 0 and later releases support multicast snooping that Jul 29, 2011 · Step 11. Let’s see if it works. 244. This feature is useful when the ISP modem/router has been replaced by the UniFi Gateway, but there is an IPTV box on the LAN that still needs to communicate with the ISP. As we have seen in the IGMP snooping lesson, switches will listen to IGMP messages and learn on which interfaces they have to forward multicast traffic. This compares to the more typical IP The newer IGMP proxy feature and the older IGMP snooping feature cannot be enabled at the same time, as both features add membership information to multicast group table. The settings are saved. Internet Group Management Protocol (IGMP) is an IPv4 protocol that a multicast receiver uses to communicate with an interface on a Palo Alto Networks® firewall and that the firewall uses to track the membership of multicast groups. The proxy triggers the boundary router connected to a PIM-SM domain to query for multicast flows and forward them to the PIM-DM domain. In this example topology, the multicast router forwards multicast traffic to the switch from the source when it receives a membership report for group 233. An IGMPv3 device supports Basic IGMPv3 Snooping Support (BISS), which includes support for the snooping features on IGMPv1 and IGMPv2 switches and for IGMPv3 membership report messages. Define the upstream and downstream interface roles. Connections: C1 connects to A1, A2, A3. Aug 15, 2018 · Step 1. Enable IGMP Snooping, use IGMP version 3, and forward Unknown Multicast Groups. A2 connects to H21, H22, etc. Click Apply. On larger, shared networks with Dante or AES67 multicast flows, IGMP Snooping greatly reduces the amount of Multicast traffic on the network by only forwarding Multicast data to the devices that request it. Enable IGMP snooping globally as well as for each specific VLAN for DM NVX connected ports. 2, you can use the CLI to enable IGMP proxy per FortiSwitch unit. Um roteador opera na camada de rede, enquanto um switch de rede pode estar informado apenas da camada 2, também conhecida como camada de enlace de dados. For most multicast deployments, you should enable the IGMP Proxy feature on all VLAN interfaces to manage all the multicast membership requirements on the controller . Configuring IGMP Proxy via CLI. Use this command to display the full contents of the IP multicast routing table. On a switch (or a Linux bridge), Multicast snooping sits at network layer 2. Figure 5-1 shows an IGMP snooping switch that sits be tween the host and the IGMP IGMP snooping is a method that network switches use to identify multicast groups, which are groups of computers or devices that all receive the same network traffic. The IGMP snooping querier disables itself if the IP address is cleared. immediate-leave ; interface interface-name {. This ensures group membership reports are flood through the network periodically to keep the Device(config)# interface gigabitethernet 1/0/0. y represents the last two octets of the NLB VIP). content_copy zoom_out_map. IGMP (on a device) sends out periodic general IGMP queries. These queries are not sent downstream, but the switch does respond to them directly. Configure the interval. The show ip igmp snooping interface command shows VLANs, IGMP version and all other IGMP snooping details. The incoming interface is correct. Devices would be responsible for filtering out the traffic that they do not want to receive. /*]]>*/. , some switches may block all unknown multicast traffic by default, when IGMP snooping is enabled, this may also affect MAC The IGMP snooping feature tracks which ports are attached to multicast-capable routers to help the routers forward IGMP membership reports. To function, Layer 3 aware devices listen to join and leave messages from clients wanting to join and leave multicast groups through use of an IGMP Querier, common setups rely on a Designated Querier (DQ) per VLAN. Configures the aging time of dynamic multicast members. Procedure. Internet Group Management Protocol (IGMP) proxy can implement multicast routing. configure. When a host wants to receive multicast traffic, its implementation of IGMP sends an IGMP Membership report The IGMP Proxy feature allows you to forward IPTV multicast traffic from your ISP on the WAN to one or more devices on the LAN. To display multicast information, use the ip maddr show subcommand, for example: inet 224. Mar 26, 2021 · IGMP Snooping helps prevent transmission of Multicast traffic to ports that don't need them. When the switch receives a group-specific query, the switch terminates the query and sends an IGMP proxy report if there is a receiver for the group. 0, the default multicast filtering mode will change from basic to IGMP/MLD snooping. This command enables the IGMP Proxy on the router. The host interfaces respond to queries according to the membership database or send join/leave messages when the database changes. Jan 16, 2022 · IGMP Snooping เป็นกลไกทางด้าน Multicas tซึ่งจะทํางานอยู่บน Layer 2 switch โดย ทางกลไกจะ Jan 2, 2010 · 2022-09-26 00:27:47 - last edited 2023-05-17 23:53:07. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Understanding IGMP Snooping † Proxy Reporting, page 38-6 † Explicit Host Tracking, page 38-7 IGMP Version 3 Support Overview IGMP snooping supports IGMP version 3 (IGMPv3). Devices That Run IGMPv1 IGMPv1 devices send IGMP queries to the “all-hosts” multicast address of 224. Feb 10, 2021 · 1. This would not work well in large network Mar 28, 2018 · Step 4. edit 7. set igmp-proxy enable. The Edit IGMP Snooping Settings window opens. Discover the benefits and applications of IGMP Proxy in enterprise, service provider, and IoT networks. SW1(config-if)#ip igmp filter 1. However, multicast traffic can slow your network by flooding all switch ports with all multicast traffic, even if the device connected to a particular port doesn’t care about the traffic We would like to show you a description here but the site won’t allow us. None, provided there really is no multicast. Example 1 Use the following commands to configure IGMP settings on a FortiSwitch port: config switch-controller managed-switch. IGMP (on a multicast router) or the IGMP snooping qu erier (on the supervisor engine) sends out periodic general IGMP queries that the switch forwards through all ports in the VLAN and to which hosts respond. A1, A2, A3 each support V1 and V2. config ports. IGMP snooping is running on core switch and access switches. 1. Re:IGMP snooping/multicasting support-Solution. OpenWrt has the package igmpproxy utility to do that. Starting in FortiOS 7. Examples. set igmp-snooping enable. BISS constrains the Nov 23, 2023 · Internet Group Management Protocol (IGMP) snooping is supported on WLC to better direct multicast packets. 0, the default multicast filtering mode is IGMP/MLD snooping. To edit the IGMP snooping settings, select the VLAN ID for the network within which multicast will be used (in this example, we are assuming that VLAN 2 is for Dante), and click “Edit”. edit <FortiSwitch_serial_number>. Jun 13, 2018 · Internet - VID 201. Configuring IGMP Snooping and Filtering This chapter describes how to configure Internet Group Management Protocol (IGMP) snooping on the Catalyst 4500 series switch. If you choose to disable the IGMP proxy, then you can do so by the following steps. It listens on a “downstream” ( LAN) interface for IGMP enabled, the IGMP snooping querier uses the IP address as the query source address. igmp-snooping {. If IGMP snooping is not enabled on vlan100, the switch floods the multicast traffic on all The IGMP proxy is a way to propagate IGMP joins across router boundaries. IGMP proxy intercepts and processes the IGMP requests from the hosts and forwards them to the upstream router. Step 7: ip igmp snooping querier version version Example: Switch (config)# ip igmp snooping querier version 2 (Optional) Selects the IGMP version number that the querier feature uses Dec 8, 2023 · When the mroute proxy service is enabled, the device periodically checks the static mroute table for (*, G) forwarding entries that match interfaces configured with the ip igmp mroute-proxy command (see Step 7) based on the IGMP query interval. IGMP snooping works pretty well but it does require a Aug 25, 2023 · When MediaServer multicasts the stream, IGMP snooping allows the switch to learn multicast groups without having the user to manually configure each switch. These messages indicate the group membership of the NLB nodes. Select the “Enable” check boxes next Figure 1: Example IGMP Snooping Topology. By default, the aging time of dynamic multicast member is 300 seconds. It enables switches to forward packets to the correct devices in their network. Set IGMP snooping to v2 or v3. IGMP needs to be configured on all VLAN interfaces on which the proxy is to be forwarded or received, and PIM-DM must be running for the Dec 1, 2022 · Routers also use IGMP to advertise multicast group memberships to neighboring switches and routers. The recommended setting is the default setting of the network switch. In addition to the default basic mode for filtering multicast traffic, vSphere Distributed Switch 6. 2 Before FortiOS 7. 1. The IGMP proxy is a way to propagate IGMP joins across router boundaries. For more information about IGMPv1 and IGMPv2 interoperability, see RFC 2236, Internet Group Management Protocol, Version 2 . E. Let’s activate it: SW1(config)#interface FastEthernet 0/2. It also configures the maximum waiting Next, in the following page, select the “Enable” check box next to IGMP Snooping Status, and click “Apply”. MX9116N-A1# show ip igmp snooping summary Maximum number of IGMP and MLD Instances: 512 Total Number of interface with IGMP Snooping enabled is: 1. Mar 19, 2024 · IGMP proxy and snooping are two techniques to reduce multicast traffic in a network. A tutorial on how to setup IGMP Proxyin Dec 26, 2023 · When you enable IGMP multicast, the NLB nodes send IGMP Join messages to the 239. Find out how to enable IGMPv3, IGMP proxy, SSM, and extended ACLs for IGMP. The IGMP snooping software responds to topology change notifications. ip igmp mroute-proxy type number. When you troubleshoot, use this command to verify: The (S,G) and (*,G) state entries from the flags. The range is 60 to 300 seconds. IGMP snooping listens to the IGMP messages and maintains a table of which ports need which multicast groups. You can activate this on a port, SVI or VLAN. MX9116N-A1# show ip igmp snooping interface Vlan10 is up, line protocol is up IGMP version is 3 IGMP v2 and v3; For detailed information about multicast routing, see RFC 5110. Enter configuration mode. Verify the configuration by checking the IGMP Query Interval field in the output of the show igmp interface command. IGMP Snooping checks IGMP packets passing through the network and configures Multicasting accordingly. Based on the IGMP query and report Example: Device(config)# igmp-snooping host-aging time 300. Sep 15, 2023 · How to Disable IGMP Proxy. set igmp-snooping-flood-reports {enable | disable} set mcast-snooping-flood-traffic {enable | disable} end. x. Where there is a match, one IGMP report is created and received on this interface. vlan v1 {. set querier-addr 10. query-interval 200; query-response-interval 0. 通过在SwitchB上配置IGMP Proxy功能可以缓解SwitchA对IGMP协议报文的处理压力。 为了保证组播源的数据可以正确的转发到用户网段，需要配置网络中的单播路由协议，实现网络层互通。 We would like to show you a description here but the site won’t allow us. IGMP Version 3. CLI: Access the Command Line Interface. Apr 25, 2012 · IGMP supports proxy reporting for IGMPv1 and IGMPv2 messages to handle group-specific queries. Apr 5, 2023 · Enable IGMP snooping. To display the IGMP snooping configuration for a specific VLAN, enter the following: Note: In this example, the IGMP snooping settings for VLAN 30 are displayed. 254. This chapter consists of the following major sections: † Overview of IGMP Snooping, page 18-1 . If the output does not display the intended configuration, repeat the configuration instructions in this example to correct it. Jul 30, 2020 · Now we configure IGMP snooping querier on all switches. For detailed information about PIM-SM, see RFC 7761. But in general, you can follow these steps. Without IGMP, a network switch would forward any multicast traffic to all switchports on the switch. The host interfaces and router interfaces perform actions based on this membership database. The Internet Group Management Protocol (IGMP) enables the administrator to manage routing and subscription to multicast traffic between networks, hosts, and routers. 2. This can usually be done through the switch’s web-based management interface or command line interface (CLI). Cisco has a document which describes the problem (and Cisco-specific solutions). Both regulate the flow of multicast on a LAN and are very similar, except for The ip igmp snooping querier last-member-query-interval command specifies the global last-member-query-interval used in snooping query packets transmitted from the switch. When MLD snooping is enabled on a VLAN, a Juniper Networks device examines MLD messages between hosts and multicast routers and learns which hosts are interested in receiving traffic for a multicast group. If IGMP snooping is not enabled on vlan100, the switch floods the multicast traffic on all IGMP Snooping without Router. 配置思路. On clicking the LAN icon, select “details” and note down the IP address displayed. set protocols igmp-proxy interface eth0 role upstream. The first step is to enable the IGMP snooping feature on your switch. For good network performance, ensure that there is only one IGMP querier in the network. g. For example, if the NLB VIP is 10. IP multicast is most often used for streaming media, such as video and voice over IP (VOIP). When this feature is enabled, the controller gathers IGMP reports from the clients, processes the reports, creates unique multicast group IDs (MGIDs) from the IGMP reports after it checks the Layer 3 multicast address and the VLAN number Jun 29, 2015 · 2)on the switches configure igmp snooping , so the traffic will be forwarded only to ports that are interested in this multicast traffic , using command IGMP snooping on the config mode. The value can be from 1 through 1024 seconds. the “Enabling the IGMP Snooping Querier” section on page 27-8. Step 5. The outgoing interface (s) is correct. Feb 17, 2022 · IGMP/MLD snooping means a switch, or in this case the Linux bridge, can “snoop” on the IGMP traffic from the elected querier and all multicast receivers on a LAN. IPTV still freezes. Values range from 1 to 25 seconds with a global default of one second. 9. Multicast & IGMP. The Internet Group Management Protocol (IGMP) is a network layer protocol that allows several In vSphere 7. IGMP proxy features: The simplest way how to do multicast routing; Can be used in topologies where PIM-SM is not suitable for some reason; Jun 20, 2024 · The IGMP Proxying is a clever way of taking the strain out of a router when dealing with multiple devices that use multicast. Oct 31, 2023 · Go to L2 Features -> Multicast -> IGMP Snooping . Summary. Example: Device(config-if)# ip igmp mroute-proxy loopback 0. Jul 16, 2022 · Multicast traffic is network traffic that is addressed to a group of IP addresses instead of to a single address. The CLI component of FASTPATH allows the end users to configure the network device and to view device settings and statistics using a serial interface or telnet session. Step 7. Enable IGMP Snooping Status and enable IGMP Snooping Querier. Multicast is the process of a host on an IP network sending data which can then be received by mutiple hosts (devices). Step 6. Enable multicast routing (IGMP Proxy) - Disable (Due to hardware limitation, IGMP proxy cannot co-exist with IPTV function. LAN Port 4 /3 - Blank. Apr 7, 2022 · Instead the OpenWrt router must act as a router for multicast packets and igmpproxy does this by listening for and proxying the IGMP requests to the ISP as well, and then enabling forwarding of the UDP packets from WAN to LAN . So use the CLI to connect to it and add the configuration: config switch vlan. And the way it reduces this strain is by intercepting the IGMP traffic from multiple users which either wish to join or leave the multicast group and then the proxy behaves as the multicast router itself by sending query messages to the hosts. BISS constrains the A： Igmp proxy和igmp snooping模式的区别在于proxy充当“代理人”的角色，即对下层主机它充当组播路由器的角色，对上层组播路由器它充当主机的角色，对下层用户发送上来的igmp report报文进行分析，而不把该报文透传到上层网络，而是自己以主机的身份向上层组播 当主IGMP Proxy接口故障时，支持表项的上游接口切换到备IGMP Proxy接口中，保证流量快速收敛；当主IGMP Proxy接口故障恢复时，表项的上游接口再回切到主IGMP Proxy接口上。 主主模式：在设备上的其他接口配置IGMP Proxy，多个主IGMP Proxy接口按照哈希算法进行负载分担。 A Switch supporting IGMP Snooping can passively snoop on IGMP Query, Report, and Leave packets transferred between IP Multicast Switches and IP Multicast hosts to determine the IP Multicast group membership. † If there is no IP address configured on the VLAN interface, the IGMP snooping querier does not start. Step 4. IGMPv3 uses source-based filtering, which enables hosts and routers to specify which source addresses should be allowed or blocked for a specific multicast group. Mar 17, 2016 · IP Multicast Internet Group Management Protocol (IGMP), which runs at Layer 3 on a multicast device, generates Layer 3 IGMP queries in subnets where the multicast traffic must be routed. But how does IGMP snooping look from the We would like to show you a description here but the site won’t allow us. igmp-snooping max-response-time time. the sender transmits the data only once and components (routers or switches) can then split that one feed into multiple identical feeds, to be received by multiple hosts. IGMP needs to be configured on all VLAN interfaces on which the proxy is to be forwarded or received, and PIM-DM must be running for the We would like to show you a description here but the site won’t allow us. This value is used for VLANs that do not have a value specified. For the VLAN that you want to enable for IGMP snooping, click on the paper/pencil icon under Operation . IGMP proxy features: The simplest way how to do multicast routing; Can be used in topologies where PIM-SM is not suitable for some reason; Sep 12, 2017 · Multicast may represent a heavy load for switch-routers (not mentioning the security aspect with potential DoS attacks). Mar 8, 2017 · Friendly Review for the Netgear Orbi (http://amzn. group-limit limit ; host-only-interface ; immediate-leave ; multicast-router-interface; O IGMP é um protocolo da camada de rede e apenas os dispositivos de rede que estão informados da camada de rede podem enviar e receber mensagens. IGMP is the control protocol for IPv4 multicast and MLD is the control protocol for IPv6 multicast. To configure Internet Group Management Protocol (IGMP) snooping, include the igmp-snooping statement: content_copy zoom_out_map. This can help prevent multicast traffic from flooding the network and reduce congestion. edit <port_name>. end. Aug 8, 2020 · In this video I talk about how a switch deals with multicast frames using IGM snooping. set protocols igmp-proxy interface eth1 role downstream. Hi, Deco supports IGMP snooping V1/2/3 and it is enabled by default. set igmp-snooping-querier enable. Configure IGMP Snooping for multicast clients in the same LAN 1. It is forwarding IGMP frames and commonly is used when there is no need for more advanced protocol like PIM. It provides guidelines, procedures, and configuration examples. IGMP là một giao thức ở network layer được sử dụng để thiết lập multicasting Set the IGMP query interval to 60 seconds or 125 seconds. That said, without an mrouter in the network, you need to configure one (or more) igmp queriers. @richaardvark. Feb 8, 2024 · Learn how IGMP Proxy works as an intermediary between hosts and multicast routers, selectively forwarding multicast traffic only to interested segments. [edit protocols igmp] user@host# set query-interval 200. ip igmp snooping {enable | disable} For example, the following command enables IGMP snooping on VLAN 2: switch (config)# vlan 2 switch (config-vlan)# ip igmp snooping enable. Navigate to the “Network Connections” on the PC and click on the “Local Area Connection”. Nov 28, 2023 · show ip mroute. If it is not, check the unicast routing table. Jan 7, 2020 · IGMP Snooping proxy is an enhanced function. By default, the vPC peer-link is considered as a multicast router port and the multicast packet is sent to the peer-link for each receiver VLAN. 255. Wrt. 2, there may be other limitations depending on the actual L2 device or operating system used. 4; Jul 29, 2021 · Giao thức IGMP là gì? IGMP là từ viết tắt của Internet Group Management Protocol là một giao thức cho phép một số thiết bị chia sẻ một địa chỉ IP để tất cả chúng có thể nhận cùng một dữ liệu. Example 1: Configuring the Interface. To change the IGMP settings of a VLAN, select its radio button and click the Edit button. Now, enter the IP address of your Router in the Mar 1, 2016 · There is a problem with IGMP snooping across switches since the IGMP message on one switch doesn't get send to the other switch, so the switch with the source will not know that the port to the other switch should receive the multicast frames. ) Click Apply. 7. Use the no command to disable IGMP snooping on a VLAN. Applicable to the latest EdgeOS firmware on all EdgeRouter models. Routers not handling multicast routing don't care. The profile above lets us block multicast group 239. 5 and is intended to alleviate the load by: From configuration mode, confirm your configuration by entering the show protocols igmp-snooping command. If a switch is located between the router and receivers, the switch must support IGMP snooping. The ip igmp filter command is what we need to activate the IGMP profile. Enable IGMP snooping on a VLAN using the following command. Essentially, IGMP snooping is a layer 2 optimization for the layer 3 IGMP. 1, the multicast address for IGMP Join messages is 239. This document describes IP multicast basics and how to configure IP multicast features, including IGMP/MLD, PIM (IPv4&IPv6), MSDP, IGMP/MLD snooping, multicast VLAN, multicast route management, static multicast MAC address, controllable multicast, and multicast network. It provides switches with a mechanism to prune multicast traffic from links that do not contain a multicast listener (an IGMP client). By default, IGMP snooping is enabled on the device. For the type and number arguments, select an interface that is facing the nondirectly connected hosts. 3)on the WLC make sure that the mDNS is enabled on the WLCm, and the mDNS profile has the chromcast service it its available services , see the link below for IGMP snooping is designed to prevent hosts on a local network from receiving traffic for a multicast group they have not explicitly joined. Answer: Yes, it's useful to limit the broadcast effects of multicast. Without IGMP snooping, switches will flood multicast traffic everywhere, treating it like broadcast traffic. mn uz ur jt zv wk cw bb zz bs