The Cisco NX-OS software is a data center-class operating system built with modularity, resiliency, and serviceability at its foundation. Based on the industry-proven Cisco NX-OS software, Cisco NX-OS helps ensure continuous availability and sets the standard for mission-critical data center environments. The highly modular design of Cisco NX-OS makes zero-effect operations a reality and enables exceptional operational flexibility.
Several new hardware and software features are introduced for the Cisco Nexus 6000 Series device and the Cisco Nexus 2000 Series Fabric Extender (FEX) to improve the performance, scalability, and management of the product line.
Cisco Nexus 6000 Series Devices
The Cisco Nexus 6000 Series includes 10- and 40-Gigabit Ethernet density in energy-efficient compact form factor switches. The Cisco Nexus 6000 Series Layer 2 and Layer 3 set allow for multiple scenarios such as direct-attach 10- and 40-Gigabit Ethernet access and high-density Cisco Fabric Extender (FEX) aggregation deployments, leaf and spine architectures, or compact aggregation to build scalable Cisco Unified Fabric in the data centers.
Cisco Nexus 6000 Series products use the same set of Cisco application-specific integrated circuits (ASICs) and a single software image across the products within the family, which offers feature consistency and operational simplicity. Cisco Nexus 6000 Series switches support robust Layer 2 and Layer 3 functions, industry-leading FEX architecture with Cisco Nexus 2000 and Cisco Nexus B22 Blade FEX, in-service software upgrades (ISSUs), and Cisco FabricPath. Operational efficiency and programmability are enhanced on the Cisco Nexus 6000 Series through advanced analytics, PowerOn Auto Provisioning (POAP), and Python/Tool Command Language (Tcl) scripting.
The Cisco Nexus devices include a family of line-rate, low-latency, lossless 10-Gigabit Ethernet, Cisco Data Center Ethernet, Fibre Channel over Ethernet (FCoE), and native Fibre Channel devices for data center applications.
For information about the Cisco Nexus 6000 Series, see the Cisco Nexus 6000 Series Platform Hardware Installation Guide.
Cisco Nexus 2000 Series Fabric Extenders
The Cisco Nexus 2000 Series Fabric Extender (FEX) is a highly scalable and flexible server networking solution that works with the Cisco Nexus 6000 Series devices to provide high-density and low-cost connectivity for server aggregation. Scaling across 1-Gigabit Ethernet, 10-Gigabit Ethernet, and 40-Gigabit Ethernet, unified fabric, rack, and blade server environments, the FEX is designed to simplify data center architecture and operations.
The FEX integrates with its parent Cisco Nexus device, which allows zero-touch provisioning and automatic configuration. The FEX provides a single point of management that supports a large numbers of servers and hosts that can be configured with the same feature set as the parent Cisco Nexus 6000 Series switch, including security and quality of service (QoS) configuration parameters. Spanning Tree Protocol (STP) is not required between the Fabric Extender and its parent switch, because the Fabric Extender and its parent switch allow you to enable a large multi-path, loop-free, active-active topology.
Software is not included with the Fabric Extender. Cisco NX-OS software is automatically downloaded and upgraded from its parent switch. For information about configuring the Cisco Nexus 2000 FEX, see the “Configuring the Fabric Extender” chapter in the Cisco Nexus 6000 Series Layer 2 Switching Configuration Guide.
Flex links are a pair of a Layer 2 interfaces (switch ports or port channels) where one interface is configured to act as a backup to the other. The feature provides an alternative solution to the Spanning Tree Protocol (STP). You can disable STP and still retain basic link redundancy. Flex links are typically configured in service provider or enterprise networks where customers do not want to run STP on the switch. If the switch is running STP, flex links are not necessary because STP already provides link-level redundancy or backup. Flex Links are supported only on Layer 2 ports and port channels, not on VLANs or on Layer 3 ports.
IEEE 1588v2 PTP
PTP is a time synchronization protocol for nodes distributed across a network. Its hardware timestamp feature provides greater accuracy than other time synchronization protocols such as the Network Time Protocol (NTP). PTP is a distributed protocol that specifies how real-time PTP clocks in the system synchronize with each other.
Note PTP is not supported on 100G CLEM.
ERSPAN v3 with PTP Timestamp
Encapsulated remote switched port analyzer (ERSPAN) is used to transport mirrored traffic in an IP network. ERSPAN supports source ports, source VLANs, and destinations on different switches, which provide remote monitoring of multiple switches across your network. ERSPAN uses a generic routing encapsulation (GRE) tunnel to carry traffic between switches.
ERSPAN consists of an ERSPAN source session, routable ERSPAN GRE-encapsulated traffic, and an ERSPAN destination session. You separately configure ERSPAN source sessions and destination sessions on different switches.
There are two types of ERSPAN—Type II (default) and type III. Type III supports all of ERSPAN type II features and adds the following enhancements:
Provides timestamp information in the ERSPAN Type III header that can be used to calculate the packet latency among edge, aggregate, and core switches.
Identifies possible traffic sources using the ERSPAN Type III header fields.
ERSPAN Type III provides configurable switch IDs that can be used to identify traffic flows across multiple switches.
CoPP (Control Plane Policing) Extended Rate
Beginning with Cisco Nexus 7.1(1)N1(1) release, you can configure an extended CoPP committed information rate (CIR) limit of up to 61,440 Kbps for each customized CoPP profile.
Class-Based Quality-of-Service MIB (cbQoSMIB)
This feature provides the Simple Network Management Protocol (SNMP) MIB that enables retrieval of class-map and policy-map configuration and statistics.
Intelligent Traffic Director (ITD)
Intelligent Traffic Director (ITD) is an intelligent, scalable clustering and load-balancing engine that addresses the performance gap between a multi-terabit switch and gigabit servers and appliances. The ITD architecture integrates Layer 2 and Layer 3 switching with Layer 4 to Layer 7 applications for scale and capacity expansion to serve high-bandwidth applications.
ITD provides adaptive load balancing to distribute traffic to an application cluster. With this feature on the Cisco Nexus 5000 Series switches, you can deploy servers and appliances from any vendor without a network or topology upgrade.
Remote Integrated Service Engine (RISE)
Cisco RISE is an architecture that logically integrates an external (remote) service appliance, such as a Citrix NetScaler Application Delivery Controller (ADC), so that the appliance appears and operates as a service module (remote line card) within the Cisco Nexus switch. The Cisco NX-OS software in which RISE is supported supports the Cisco Nexus 5500, 5600, and 6000 Series switches.
100 Mbps Support on 2348TQ and 2332TQ
The Cisco Nexus 7.1(1)N1(1) release supports 100 Mbps speed on the host interfaces of Cisco Nexus 2348TQ and 2332TQ.
New Hardware Features in Cisco NX-OS Release 7.1(1)N1(1)
Cisco NX-OS Release 7.1(1)N1(1) supports the following new hardware:
Cisco Nexus N5648Q—Support for 48 QSFP 40G ports. It has 24 fixed QSFP ports and support for two GEM slots that can support an additional 12 QSFP ports per GEM slot.
BPDU Guard can be can be activated on disallowed edge trunk VLANs. This is done by configuring both sides of the link as either trunks or access interfaces.
CTS with FabricPath
The Cisco TrustSec security architecture has been extended to support Cisco FabricPath environments including those using VPC+. CTS packet classification can occur before or as traffic enters the fabric, at which point packet tags are preserved through the fabric for the purpose of applying security policy to the data path.
Dynamic ARP Inspection Enhancement
Dynamic ARP Inspection (DAI) can validate ARP packets against user-configured ARP access control lists (ACLs). DAI can be configured to drop ARP packets when the IP/MAC addresses in the packets are invalid. This is done by configuring ARP based ACLs.
IPv6 vPC/vPC+ Keepalive Support
IPv6 support for vPC/vPC+ provides IPv6 capabilities for the vPC/vpc+ keepalive from the mgmt0 out-of-band interface as well from the build-in front ports via SVI.
Isolate and Maintenance Mode Enhancement
Provides the ability to gracefully eject a switch and isolate it from the network so that debugging or an upgrade can be performed. The switch is removed from the regular switching path and put into a maintenance mode. Once maintenance on the switch is complete, you can bring the switch into full operational mode.
In service software updates (ISSUs) are limited to the three previous releases.
Note Two-level upgrades can be done to get to the latest release 7.1(0)N1(1a). For example, the customer can upgrade from 6.0(2)N2(X) to 7.0(3)N1(1), 7.0(4)N1(1) or 7.0(5)N1(1), and then to 7.1(0)N1(1a).
Long Distance Support
Long distance support (20 km/10G & 3 km/40G) for FCoE.
Improves efficiency in the usage of Multicast Expansion Table (MET) entries in the hardware.
Open Management Infrastructure
Open Management Infrastructure (OMI) is no longer supported.
Password Length Enhancement
The following commands have been added to provide the ability to configure the minimum and maximum length of a password:
userpassphrase min-length length
userpassphrase max-length length
show userpassphrase length
Syslog Message as SNMP Trap
The following features has been added:
User Interface for Persistent Logging
Syslog SNMP Traps
Syslog Message Format
Unified Fabric Solution (previously called Dynamic Fabric Automation (DFA))
This software release is the second release to support enhancements to Cisco's Unified Fabric Solution.
Unified Fabric focuses on simplifying, optimizing, and automating data center fabric environments by offering an architecture based on four major pillars: Fabric Management, Workload Automation, Optimized Networking, and Virtual Fabrics.
Each of these pillars provides a set of modular functions which can be used together, or independently, for ease of adoption of new technologies in the data center environment.
Allows for the merging of separate Layer 2 domains that might reside in a two data centers that are connected through some form of Data Center Interconnect (DCI).
Supports automatic VLAN provisioning.
vPC Border Leaf Support
Supports redundant border leafs in a vPC+ pair.
New Hardware Features in Cisco NX-OS Release 7.1(0)N1(1a)
Cisco NX-OS Release 7.1(0)N1(1a) supports the following new hardware:
Cisco Nexus 2348TQ FEX (N2K-C2348TQ-10GE)
100 G LEM (N5696-M4C)
– To enable 100G LEM N5696-M4C, the required BIOS version is 2.8.0 or above for EF chassis. If the LEM’s BIOS version is lower than 2.8.0, ISSU is required as it facilitates a built-in BIOS update procedure.
– For EF-CR chassis, the required BIOS version is 2.1.0 or above.
– For Microcontroller Firmware—The required version is 22.214.171.124 or above for EF-CR chassis and 126.96.36.199 or above for EF chassis.
– For N5696Q, native support has been added for 100G LEM N5696-M4C.
– Added support for 100G LEM N5696-M4C with N6004EF chassis. 100G LEM N5696-M4C module must have BIOS version 2.8.0 or above for N6004EF chassis.
H7 Power Supply Support—support for forward air flow (FAF) (NXA-PHV-1100W) and reverse air flow (RAF) (NXA-PHV-1100W-B) with both AC and DC power source.
10 G DWDM
LR4 Optics—WSP-Q40GLR4L (QSFP40G-LR4-LITE)
New Software Features in Cisco NX-OS Release 7.0(6)N1(1)
There are no new software features in this release.
New Hardware Features in Cisco NX-OS Release 7.0(6)N1(1)
There are no new hardware features in this release.
New Software Features in Cisco NX-OS Release 7.0(5)N1(1a)
There are no new software features in this release.
New Hardware Features in Cisco NX-OS Release 7.0(5)N1(1a)
There are no new hardware features in this release.
New Software Features in Cisco NX-OS Release 7.0(5)N1(1)
There are no new software features in this release.
New Hardware Features in Cisco NX-OS Release 7.0(5)N1(1)
There are no new hardware features in this release.
New Software Features in Cisco NX-OS Release 7.0(4)N1(1)
There are no new software features in this release.
New Hardware Features in Cisco NX-OS Release 7.0(4)N1(1)
Cisco NX-OS Release 7.0(4)N1(1) supports the following new hardware feature:
Cisco Nexus 2348UPQ support for QSA (FET-10G, SFP-10G-SR, SFP-10G-ER)
New Software Features in Cisco NX-OS Release 7.0(3)N1(1)
Cisco NX-OS Release 7.0(3)N1(1) is a maintenance release that includes bug fixes and the following software features and enhancements:
Dynamic Fibre Channel over Ethernet (FCoE) using DFA enables I/O consolidation. It permits both LAN and SAN traffic to coexist on the same switch and the same wire.
FEX Based ACL Classification
The FEX-based ACL Classification feature uses TCAM resources on a FEX to perform ACL-based packet classification of incoming packets on the switch. When QoS policies are processed on a FEX, the policies are enforced on the switch and on the associated FEX or FEXes.
New Hardware Features in Cisco NX-OS Release 7.0(3)N1(1)
Cisco NX-OS Release 7.0(3)N1(1) supports the following new hardware:
Cisco Nexus 2348UPQ FEX (N2K-C2348UPQ)
New Software Features in Cisco NX-OS Release 7.0(2)N1(1)
Cisco NX-OS Release 7.0(2)N1(1) is a maintenance release that includes bug fixes and the following software features and enhancements:
The ACL logging feature allows you to monitor IPv6 ACL flows and to log dropped packets on an interface.
Dynamic FCoE Using FabricPath
Dynamic FCoE extends the capability and reliability of storage networks by leveraging FabricPath technology to create logical separation of SAN A and SAN B. FCoE VFCs and Interswitch-Links (ISLs) are dynamically configured, simplifying multihop FCoE deployments in leaf-spine topologies.
Layer 2 CTS Support
The Cisco TrustSec security architecture builds secure networks by establishing clouds of trusted network devices. Cisco TrustSec also uses the device information acquired during authentication for classifying, or coloring, the packets as they enter the network. This packet classification is maintained by tagging packets on ingress to the Cisco TrustSec network so that they can be properly identified for the purpose of applying security and other policy criteria along the data path.
New Hardware Features in Cisco NX-OS Release 7.0(1)N1(1)
Cisco NX-OS Release 7.0(1)N1(1) support the following new hardware:
Cisco Nexus 5672UP
The Cisco Nexus 6004 Unified Port Linecard Expansion Module - N6004X-M20UP
Cisco Nexus B22IBM FEX - N2K-B22IBM-P
New Software Features in Cisco NX-OS Release 7.0(0)N1(1)
Cisco NX-OS Release 7.0(0)N1(1) is a major release that includes bug fixes and the following software features and enhancements:
Anycast HSRP is a FabricPath-based feature in which the traditional HSRP can be extended to an n-Gateway solution with all the gateways actively forwarding traffic. This feature supports active load balancing of traffic among all the gateways configured apart for redundancy. A maximum of 4 Gateways is supported.
This feature provides the capability of advanced analytics for network visibility and management. Critical analytics for network monitoring is supported including Latency Based SPAN, SPAN on Drop, Micro-Burst Monitor and Switch Latency.
Latency-based SPAN can be used to monitor any packet from an interface when the latency on that interface exceeds the configured threshold.
SPAN on Drop can be used to configure SPAN on particular packets which would otherwise get dropped due to congestion, and is used for known unicast packets.
Micro-Burst Monitoring is supported per port both in ingress and egress direction and can be selectively enabled or disabled in either direction.
Switch Latency provides instantaneous latency and histogram data between a pair of ports and provides minimum, average, and maximum latency between the slected pairs of ports.
Dynamic Fabric Automation
This software release is the first release to support Cisco's Evolutionary Data Center Fabric solution called Dynamic Fabric Automation (DFA). DFA is evolutionary and is based on the industry leading Unified Fabric solution.
DFA focuses on simplifying, optimizing and automating data center fabric environments by offering an architecture based on four major pillars namely Fabric Management, Workload Automation, Optimized Networking and Virtual Fabrics. Each of these pillars provide a set of modular functions which can be used together or independently for easiness of adoption of new technologies in the data center environment.
When the Forwarding Information Base (FIB) table is 90% full, the following messages is displayed:
FIB_TCAM_RESOURCE_EXHAUSTION:FIB TCAM usage is at 90 percent.
ECN with WRED
Currently, the congestion control and avoidance algorithms for Transmission Control Protocol (TCP) are based on the idea that packet loss is an appropriate indication of congestion on networks transmitting data using the best-effort service model. When a network uses the best-effort service model, the network delivers data if it can, without any assurance of reliability, delay bounds, or throughput. However, these algorithms and the best-effort service model are not suited to applications that are sensitive to delay or packet loss (for instance, interactive traffic including Telnet, web-browsing, and transfer of audio and video data). Weighted Random Early Detection (WRED), and by extension, Explicit Congestion Notification (ECN), solves this problem.
ERSPAN with ACL Filtering
With ERSPAN traffic the destination is remote and the overall impact of bandwidth congestion can be significant. The ERSPAN with ACL filtering feature allows you to filter ERSPAN traffic so that you can reduce bandwidth congestion. To configure ERSPAN with ACL filtering, you use ACL’s for the session to filter out traffic that you do not to span. An ACL is a list of permissions associated to any entity in the system; in the context of a monitoring session, an ACL is a list of rules which results in the spanning of traffic that matches the ACL criteria, saving bandwidth for more meaningful data. The filter would apply on all sources in the session (VLAN or interface).
FabricPath Operations, Administration, and Management
Support for Fabric Path Operations, Administration and Management has been added in this software release.
Intermediate System to Intermediate System Protocol
Intermediate System to Intermediate System (IS-IS) is an Interior Gateway Protocol (IGP) based on Standardization (ISO)/International Engineering Consortium (IEC) 10589. Cisco Nexus devices support Internet Protocol version 4 (IPv4) and Internet Protocol version 6 (IPv6). IS-IS is a dynamic link-state routing protocol that can detect changes in the network topology and calculate loop-free routes to other nodes in the network. Each router maintains a link-state database that describes the state of the network and sends packets on every configured link to discover neighbors. IS-IS floods the link-state information across the network to each neighbor. The router also sends advertisements and updates on the link-state database through all the existing neighbors.
Layer 2 Bidirectional Forwarding Detection
The Bidirectional Forwarding Detection (BFD) provides fast forwarding-path failure detection times for media types, encapsulations, topologies, and routing protocols. You can use BFD to detect forwarding path failures at a uniform rate, rather than at variable rates for different protocol hello mechanisms. BFD makes network profiling and planning easier and reconvergence time consistent and predictable.
Multi-Destination Switch Port Analyzer
Local Switch Port Analyzer (SPAN) and SPAN-on-Drop sessions can support multiple destination ports. This allows traffic in a single local SPAN session or a SPAN-on-Drop session also to be monitored and sent to multiple destinations.
A Multi-Destination Tree (MDT), also referred to as a forwarding tag or ftag, is a spanning-tree used for forwarding packets within a topology. A topology has two MDTs/ ftags: topology 0 has ftag 1 and 2, topology 1 has ftag 3 and 4.
The OpenFlow feature is a specification from the Open Networking Foundation (ONF) that defines a flow-based forwarding infrastructure (L2-L4 Ethernet switch model) and a standardized application programmatic interface (protocol definition) to learn capabilities, add and remove flow control entries and request statistics. OpenFlow allows a controller to direct the forwarding functions of a switch through a secure channel.
One Platform Kit (OnePK)
Support has been added for One Platform Kit (onePK) Turbo API. OnePK is a cross-platform API and software development kit that enables you to develop applications that interact directly with Cisco networking devices. onePK provides you access to networking services by using a set of controlled APIs that share the same programming model and style. For more information, see the following URL:
Intermediate System to Intermediate System (IS-IS) uses the overload bit to tell other routers not to use the local router to forward traffic but to continue routing traffic destined for that local router.
Port Channel Max Links
The Port Channel Max Links feature defines the maximum number of bundled ports allowed in an LACP port channel.
Q-in-Q VLAN Tunneling
A Q-in-Q VLAN tunnel enables a service provider to segregate the traffic of different customers in their infrastructure, while still giving the customer a full range of VLANs for their internal use by adding a second 802.1Q tag to an already tagged frame.
The Sampled NetFlow feature samples incoming packets on an interface. The packets sampled then qualify to create flows. Sampled NetFlow reduces the amount of export data sent to the collector by limiting the number of packets that create flows and the number of flows. It is essential when flows are created on a line card or external device, instead of on the forwarding engine.
Switch Port Analyzer with ACL Filtering
The Switch Port Analyzer (SPAN) with Access Control List (ACL) filtering feature allows you to filter SPAN traffic so that you can reduce bandwidth congestion. To configure SPAN with ACL filtering, you use ACL’s for the session to filter out traffic that you do not want to span. An ACL is a list of permissions associated to any entity in the system; in the context of a monitoring session, an ACL is a list of rules which results in spanning only the traffic that matches the ACL criteria, saving bandwidth for more meaningful data. The filter can apply to all sources in the session.
Static/Dynamic Network Address Translation
Network Address Translation (NAT) enables private IP internetworks that use nonregistered IP addresses to connect to the Internet. NAT operates on a device, usually connecting two networks, and translates private (not globally unique) IP addresses in the internal network into legal IP addresses before packets are forwarded to another network. You can configure NAT to advertise only one IP address for the entire network to the outside world. This ability provides additional security, effectively hiding the entire internal network behind one IP address.
You can create and administer up to 16 templates to resize the regions in ternary content-addressable memory (TCAM).
The VN-Segment feature defines a new way to "tag" packets on the wire replacing the traditional 802.1Q VLAN tag. This feature uses a 24-bit tag also referred to as a Virtual Network Identifier (VNI). CE links (access and trunk) carry traditional VLAN tagged/untagged frames. These are the VN-Segment Edge ports.
Web Cache Control Protocol v2
WCCPv2 specifies interactions between one or more Cisco NX-OS routers and one or more cache engines. WCCPv2 transparently redirects selected types of traffic through a group of routers. The selected traffic is redirected to a group of cache engines to optimize resource usage and lower response times.
New Hardware Features in Cisco NX-OS Release 7.0(0)N1(1)
Cisco NX-OS Release 7.0(0)N1(1) supports the following new optics:
Upgrading or Downgrading to a New Release
This section describes the upgrade and downgrade paths that are supported for Cisco NX-OS Release 7.1(1)N1(1) on the Cisco Nexus device.
Table 4 shows the upgrade and downgrade possibilities for Cisco NX-OS Release 7.1(1)N1(1). For more information, see the Cisco Nexus 6000 Series NX-OS Software Upgrade and Downgrade Guide, Release 7.1(1)N1(1).
Note Doing a disruptive upgrade between incompatible images will result in loss of certain configurations such as unified ports, breakout, and FEX configurations. See CSCul22703 for details.
Table 5 shows the upgrade and downgrade possibilities for Cisco NX-OS Release 7.0(6)N1(1). For more information, see the Cisco Nexus 5500 Series NX-OS Software Upgrade and Downgrade Guide, Release 7.0(6)N1(1).
Note Disruptive upgrade is required before configuring VLAN translation on FEX for 7.1(0)N1(1b).
This section describes the limitations for Cisco NX-OS Release 7.x.
The Server Virtualization Switch (SVS) connection is not deleted during a rollback when NIV is enabled. To resolve this issue, delete the current SVS connection and reapply the original SVS connection. For details, see CSCts17033.
If you configure a Cisco Nexus 2248TP port to 100 Mbps instead of autonegotiation, then autonegotiation does not occur, which is the expected behavior. Both sides of the link should be configured to both hardwired speed or both autonegotiate.
no speed —Autonegotiates and advertises all speeds (only full duplex).
speed 1000 —Autonegotiates only for an 802.3x pause.
speed 100 —Does not autonegotiate; pause cannot be advertised. The peer must be set to not autonegotiate and fix at 100 Mbps (similar to the N2248TP). For details, see CSCte81998.
When a private VLAN port is configured as a TX (egress) SPAN source, the traffic seen at the SPAN destination port is marked with the VLAN of the ingressed frame. There is no workaround.
In large-scale configurations, some Cisco Nexus 2000 Series Fabric Extenders might take up to 3 minutes to appear online after entering the reload command. A configuration can be termed large scale when the maximum permissible Cisco Nexus 2000 Series Fabric Extenders are connected to a Cisco Nexus 6000 Series switch, all host-facing ports are connected, and each host-facing interface has a large configuration that supports the maximum permissible ACEs per interface.
The Cisco Nexus 2148 Fabric Extender does not support frames with the dot1q vlan 0 tag.
VACLs of more than one type on a single VLAN are unsupported. Cisco NX-OS software supports only a single type of VACL (either MAC, IPv4, or IPv6) applied on a VLAN. When a VACL is applied to a VLAN, it replaces the existing VACL if the new VACL is a different type. For instance, if a MAC VACL is configured on a VLAN and then an IPv6 VACL is configured on the same VLAN, the IPv6 VACL is applied, and the MAC VACL is removed.
A MAC ACL is applied only on non-IP packets. Even if there is a match eth type = ipv4 statement in the MAC ACL, it does not match an IP packet. To avoid this situation, use IP ACLs to apply access control to the IP traffic instead of using a MAC ACL that matches the EtherType to IPv4 or IPv6.
Multiple boot kickstart statements in the configuration are not supported.
If you configure Multiple Spanning Tree (MST) on a Cisco Nexus 6000 Series switch, avoid partitioning the network into a large number of regions.
By design, vEth interfaces do not share the underlying behavior of a vPC port. As a result, a VLAN is not suspended when the peer switch suspends it. For example, when you shut a VLAN on a primary switch, the VLAN continues to be up on the secondary switch when the vEth interface is on a FEX. When the VLAN on the primary switch goes down, the VLAN on the vEth interface on the primary is suspended, but the vEth on the secondary switch remains up because it is an active VLAN on the secondary switch.
The packet length in the IP GRE header of a packet exiting from the switch is not equal to the MTU value configured in the ERSPAN source session. This is true for SPAN or ERSPAN. The Cisco Nexus 6000 Series switch terminates in multiples of 16 bytes. If MTU is configured as 100 bytes, then the actual truncated packet is 96 bytes.
Unknown unicast packets in FabricPath ports are counted as multicast packets in interface counters. This issue occurs when unknown Unicast packets are sent and received with a reserved multicast address (that floods to a VLAN) in the outer FabricPath header, and the Cisco Nexus 6000 Series switch increments the interface counter based on the outer FabricPath header. As a result, Multicast counters are incremented. There is no workaround for this issue.
In an emulated switch setup, an inband keepalive does not work. The following steps are recommended for peer keepalive over SVI when a switch is in FabricPath mode:
– Use a dedicated front panel port as a vPC+ keepalive. The port should be in CE mode.
– Use a dedicated VLAN to carry the keepalive interface. The VLAN should be a CE VLAN.
– Add the management keyword to the corresponding SVI so that the failure of a Layer 3 module will not bring down the SVI interface.
– Enter the dual-active exclude interface-vlan keepalive-vlan command to prevent the SVI from going down on the secondary when a peer-link goes down.
The limit of the table that holds the Router MAC and Virtual MAC entries for determining packet routing or switching is 500 entries. The Virtual MAC entries, the MAC used for HSRP/VRRP that is also programmed in this table, can be shared across multiple Layer 3 interfaces. If SVIs 1–100 all have the same group number configured, just one entry needs to be programmed in this table. We recommend that you configure the same group ID across all or multiple Layer 3 interfaces/SVIs. If multiple group IDs are configured on an Layer 3 interface, we recommend that you configure the same set of group IDs across all or multiple Layer 3 interfaces. This configuration supports HSRP/VRRP on more interfaces.
The maximum IP MTU that can be set on Layer 3 interfaces running Layer 3 protocols is 9192 because of the internal header used inside the switch. The related network-qos policy must be set to 9216.
Limitations on the Cisco Nexus 6000
The limitations on the Cisco Nexus 6000 Series switch are as follows:
The SPAN limitations on Fabric Extender ports are as follows:
On a Cisco Nexus device, if the SPAN source is a FEX port, the frames will always be tagged when leaving the SPAN destination.
On a Cisco Nexus 6000 Series switch, if the SPAN source is an access port on a switch port or FEX port, the spanned frames at the SPAN destination will be tagged.
On a Cisco Nexus 6000 Series switch, if the SPAN source is on an access port on the switch port, the frames will not be tagged when leaving the SPAN destination.
Ports on a FEX can be configured as a tx-source in one session only.
If two ports on the same FEX are enabled to be tx-source, the ports need to be in the same session. If you configure a FEX port as a tx-source and another port belonging to the same FEX is already configured as a tx-source on a different SPAN session, an error is displayed on the CLI.
In the following example, Interface Ethernet100/1/1 on a FEX 100 is already configured as a tx-source on SPAN session-1:
swor28(config-monitor)# show running-config monitor
monitor session 1
source interface Ethernet100/1/1 tx
destination interface Ethernet1/37
If you add an interface Ethernet100/1/2 as a tx-source to a different SPAN session (session-2) the following error appears:
ERROR: Eth100/1/2: Ports on a fex can be tx source in one session only
When a FEX port is configured as a tx-source, the multicast traffic is spanned on all VLANs that the tx-source port is a member of. The FEX port sends out only multicast packets that are not filtered by IGMP snooping. For example, if FEX ports 100/1/1–12 are configured on VLAN 11 and the switch port 1/5 sends multicast traffic on VLAN 11 in a multicast group, and hosts connected to FEX ports 100/1/3–12 are interested in receiving that multicast traffic (through IGMP), then that multicast traffic goes out on FEX ports 100/1/3–12, but not on 100/1/1–2.
If you configure SPAN Tx on port 100/1/1, although the multicast traffic does not egress out of port 100/1/1, the SPAN destination does receive that multicast traffic, which is due to a design limitation.
When a FEX port is configured as both SPAN rx-source and tx-source, broadcast non-IGMP Layer-2 multicast frames as well as unknown unicast frames originating from that port might be seen twice on the SPAN destination: once on the ingress and once on the egress path. On the egress path, the frames are filtered by the FEX to prevent them from going out on the same port on which they were received. For example, if FEX port 100/1/1 is configured on VLAN 11 and is also configured as SPAN rx-source and tx-source and a broadcast frame is received on that port, the SPAN destination recognizes two copies of the frame, even though the frame is not sent back on port 100/1/1.
A FEX port cannot be configured as a SPAN destination. Only a switch port can be configured and used as a SPAN destination.
With a SPAN on Latency session, FEX ports cannot be configured as source or destination.
Layer 3 Limitations
In a vPC topology, two Cisco Nexus 6000 Series switches configured as vPC peer switches need to be configured symmetrically for Layer 3 configurations such as SVIs, a peer gateway, routing protocol and policies, and RACLs.
Note vPC consistency check does not include Layer 3 parameters.
This section includes the open and resolved caveats for this release. Each caveat has a link to the Bug Toolkit, where you can find details.
MTU option in SOL throws an error message when configured.
The Cisco Management Information Base (MIB) list includes Cisco proprietary MIBs and many other Internet Engineering Task Force (IETF) standard MIBs. These standard MIBs are defined in Requests for Comments (RFCs). To find specific MIB information, you must examine the Cisco proprietary MIB structure and related IETF-standard MIBs supported by the Cisco Nexus 6000 Series switch.
The MIB Support List is available at the following FTP site:
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