Cisco Catalyst 9300 Series Switches MACsec Encryption: Настройка и ограничения (EN)

Prerequisites for MACsec Encryption

Configuring MACsec Encryption Prerequisites for MACsec Encryption, on page 1 Restrictions for MACsec Encryption, on page 2 Information About MACsec Encryption, on page 3 How to Configure MACsec Encryption, on page 12 Configuration Examples for MACsec Encryption, on page 36 Additional References for MACsec Encryption, on page 55 Feature History for MACsec Encryption, on page 56 Prerequisites for MACsec Encryption Prerequisites for MACsec Encryption This section list the prerequisites for MACsec encryption: • Enable the ssci-based-on-sci command while configuring MACsec encryption on the device to allow interoperability with non-Cisco and non-IOS XE devices.

• Ensure that 802.1x authentication and AAA are configured on your device. • You must configure the flowcontrol receive desired command on all MACsec-enabled ports to enable flowcontrol explicitly. Prerequisites for Certificate-Based MACsec This section list the prerequisites for Certificate-Based MACsec: • Ensure that you have a Certificate Authority (CA) server configured for your network. • Generate a CA certificate. • Ensure that you have configured Cisco Identity Services Engine (ISE) Release 2.0. • Ensure that both the participating devices, the CA server, and Cisco Identity Services Engine (ISE) are synchronized using Network Time Protocol (NTP).

If time is not synchronized on all your devices, certificates will not be validated. Configuring MACsec Encryption 1

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Restrictions for MACsec Encryption

Restrictions for MACsec Encryption • For C9300-48UXM and C9300-48UN switch models, MACsec is supported only on the first 16 downlink network ports and on all uplink network module ports. MACsec is not supported on the last 32 downlink network ports of C9300-48UXM and C9300-48UN switch models. • MACsec configuration is not supported on EtherChannel ports. Instead, MACsec configuration can be applied on the individual member ports of an EtherChannel. To remove MACsec configuration, you must first unbundle the member ports from the EtherChannel, and then remove it from the individual member ports. • MACsec with MKA is supported only on point-to-point links.

• Cisco IOS XE supports only MKA version 1. This causes MACsec interoperability issues when connecting to third-party devices that require MKA version 2 or higher. • GCM-AES-256 and XPN cipher suites (GCM-AES-XPN-128 and GCM-AES-XPN-256) are supported only with Network Advantage license. • The MACsec Cipher announcement is not supported for MACsec Extended Packet Numbering (XPN) Ciphers and switch-to-switch MACsec connections. • MACsec XPN Cipher Suites are not supported in switch-to-host MACsec connections. • MACsec XPN Cipher Suites do not provide confidentiality protection with a confidentiality offset, and these together are not supported in switch-to-switch MACsec connections.

• As per IEEE standards, the maximum value of replay window is 2 30-1 for MACsec XPN Cipher Suites. Even if you configure a higher value than this, it will be restricted to 2 30-1 only. • Certificate-based MACsec is supported only if the access-session is configured as closed or in multiple-host mode. None of the other configuration modes are supported. • If the dot1q tag vlan native command is configured globally, the dot1x reauthentication will fail on trunk ports. • MACsec switch-to-host connections in an overlay network are not supported. • MACsec is not supported with Multicast VPN (mVPN). • MACsec switch-to-host connections are not supported on Software-Defined Access deployments.

• Access control options are only applicable to switch-to-switch MACsec. These options are not supported for switch-to-host MACsec. • The should-secure access mode is supported on switch-to-switch ports only using PSK authentication. • PSK fallback key chain is not supported on Ethernet Virtual Circuit (EVC), point-to-multipoint cases, and Security Association Protocol (SAP). • PSK fallback key chain supports infinite lifetime with one key only. The connectivity association key name (CKN) ID used in the fallback key chain must not match any of the CKN IDs used in the primary key chain.

• EAPOL packets of EtherType 0x888E are not intercepted by the interface if MACsec or dot1x is not enabled on the interface. Configuring MACsec Encryption Restrictions for MACsec Encryption Configuring MACsec Encryption 2

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MACsec Encryption Overview

• If there are any intermediate switches present between two MACsec endpoints, any P2P protocols like STP or CDP will not work. • Network-Based Application Recognition (NBAR) is not supported on MACsec switch-to-host connections. • RSPAN or ERSPAN does not capture encrypted packets at egress and decrypted packets at ingress for MACsec enabled interfaces. Information About MACsec Encryption The following sections provide information about MACsec encryption. Recommendations for MACsec Encryption This section list the recommendations for configuring MACsec encryption: • Use the confidentiality (encryption) offset as 0 in switch-to-host connections.

• Use Bidirectional Forwarding and Detection (BFD) timer value as 750 milliseconds for 10Gbps ports and 1.25 seconds for any port with speed above 10Gbps. • Execute the shutdown command, and then the no shutdown command on a port, after changing any MKA policy or MACsec configuration for active sessions, so that the changes are applied to active sessions. • Use Extended Packet Numbering (XPN) Cipher Suite for port speeds of 40Gbps and above. • Set the connectivity association key (CAK) rekey overlap timer to 30 seconds or more. • Do not use Cisco TrustSec Security Association Protocol (SAP) MACsec encryption for port speeds above 10Gbps.

• Do not enable both Cisco TrustSec SAP and uplink MKA at the same time on any interface. • Use MACsec MKA encryption. • Use the macsec replay-protection window-size command to avoid packet drops for WAN MACsec configuration. • Do not use the delay-protection command when defining MKA policy if MACsec scale sessions are configured. MACsec Encryption Overview MACsec is the IEEE 802.1AE standard for authenticating and encrypting packets between two MACsec-capable devices. Catalyst switches support 802.1AE encryption with MACsec Key Agreement (MKA) on switch-to-host links for encryption between the switch and host device.

The switch also supports MACsec encryption for switch-to-switch (inter-network device) security using both Cisco TrustSec Network Device Admission Control (NDAC), Security Association Protocol (SAP) and MKA-based key exchange protocol. Configuring MACsec Encryption Information About MACsec Encryption Configuring MACsec Encryption 3

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Media Access Control Security and MACsec Key Agreement

When switch-to-switch MACSec is enabled, all traffic is encrypted, except the EAP-over-LAN (EAPOL) packets. Note Link layer security can include both packet authentication between switches and MACsec encryption between switches (encryption is optional). Link layer security is supported on SAP-based MACsec. Table 1: MACsec Support on Switch Ports Cisco TrustSec and Cisco SAP are meant only for switch-to-switch links and are not supported on switch ports connected to end hosts, such as PCs or IP phones. MKA is supported on switch-to-host facing links as well as switch-to-switch links.

Host-facing links typically use flexible authentication ordering for handling heterogeneous devices with or without IEEE 802.1x, and can optionally use MKA-based MACsec encryption. Cisco NDAC and SAP are mutually exclusive with Network Edge Access Topology (NEAT), which is used for compact switches to extend security outside the wiring closet. Media Access Control Security and MACsec Key Agreement MACsec, defined in 802.1AE, provides MAC-layer encryption over wired networks by using out-of-band methods for encryption keying. The MACsec Key Agreement (MKA) Protocol provides the required session keys and manages the required encryption keys.

MKA and MACsec are implemented after successful authentication using the certificate-based MACsec or Pre Shared Key (PSK) framework. A switch using MACsec accepts either MACsec or non-MACsec frames, depending on the policy associated with the MKA peer. MACsec frames are encrypted and protected with an integrity check value (ICV). When the switch receives frames from the MKA peer, it decrypts them and calculates the correct ICV by using session keys provided by MKA. The switch compares that ICV to the ICV within the frame. If they are not identical, the frame is dropped.

The switch also encrypts and adds an ICV to any frames sent over the secured port (the access point used to provide the secure MAC service to a MKA peer) using the current session key. The MKA Protocol manages the encryption keys used by the underlying MACsec protocol. The basic requirements of MKA are defined in 802.1x-REV. The MKA Protocol extends 802.1x to allow peer discovery with confirmation of mutual authentication and sharing of MACsec secret keys to protect data exchanged by the peers. Note Starting with Cisco IOS XE 16.12.1 release, support for MKA with high availability has been introduced for Cisco Catalyst 9300 Series Switches.

The high availability feature enables a pair of route processors to act as backup for each other. With high availability support for MKA if there is an active RP failure, the stand-by RP takes over existing MKA sessions in a minimally-disruptive switchover. The EAP framework implements MKA as a newly defined EAP-over-LAN (EAPOL) packet. EAP authentication produces a master session key (MSK) shared by both partners in the data exchange.

Entering Configuring MACsec Encryption Media Access Control Security and MACsec Key Agreement Connections MACsec Support Switch-to-Host MACsec MKA Encryption Switch-to-Switch MACsec MKA encryption (recommended) Cisco TrustSec SAP Configuring MACsec Encryption 4

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